Anything that can be deemed an "interpromotional match" can be considered a crossover of one talent for another promotion. Though Lucha Libre Internacional and The Universal Wrestling Association were founded by disgruntled EMLL employees who thought it was time to leave, they would later reach working agreements to do joint shows with CMLL.
SMW did quite a few, some of the more memorable cases being with ECW (surprise appearance by Jim Cornettenote Though this happened over a year after SMW folded and was part of the WWF-ECW crossover mentioned in the next entry), World Wrestling Federation (tag team champions appeared on Survivor Series) and the National Wrestling Alliance (where Chris Candido won their World Heavyweight Title belt, not that it is recognized). There was also an attempt at one with WCW that ended up being aborted before it really got started after Bill Watts was fired as WCW booker and replaced with Eric Bischoff.
During the ECW invasion storyline in 1997, Jerry Lawler appeared on ECW programming despite being contracted by the WWE. It was actually a work, as Vince had actually been attempting to help ECW be recognized, with Paul Heyman making several appearances on Raw during the angle.
After ECW World Heavyweight ChampionMike Awesome appeared on the April 10, 2000WCW Monday Nitro while still holding the title, Paul Heyman filed an injunction to prevent Awesome from appearing on WCW TV. This led to the one-of-a-kind situation where Tazz, a WWE-contracted wrestler, defeated Awesome, a WCW-contracted wrestler, for the ECW World Heavyweight Title.note Tazz then lost the belt to ECW's Tommy Dreamer.
Perhaps the most well known crossover in wrestling happened on the last episode of WCW Monday Nitro, March 26, 2001. After Vince McMahon's purchase of the promotion, a simulcast was scheduled, with Vince on Raw bragging about how he bought his competition, while Nitro featured the WCW talent wrestling for perhaps their last time on television. The final minutes, however, proved to be the most memorable. On Nitro, Shane McMahon made an appearance on Nitro (in Panama City, FL), while Vince was at the Raw location (in Cleveland, OH). The titantron showed Shane on Raw, while Nitro had its Nitrovision show Vince. The segment was to begin the invasion storyline (and that, in kayfabe, that Shane was the actual owner). It was memorable in that both TNT and TNN were basically broadcasting the same thing during those final ten minutes or so, but in different settings. The final wrestling-related segment to ever air on TNT (until AEW Dynamite premiered in 2019) was an ad for WrestleMania.
After the WWE brand split, any match that had a Raw talent going up against a SmackDown! talent was considered this, and thus, you got a good bit of cross overs between the two brands. This was further jettisoned with the "Supershows", where Raw and Smack Down stars were on the same shows (to the point where from August of 2011 to the Raw 1000th episode, Raw was renamed the "Raw Supershow" with the word "supershow" being tacked on to the Raw logo in the style of the Smack Down logo.
Carlito would go beyond most WWE wrestlers, as he continued to appear at WWC events even after being called up to the active WWE roster. Appearances for other promotions are usually reserved for inactive wrestlers such as commentator Jerry Lawler.
Unusually for a WWE developmental territory (as opposed to a talent scout) Ohio Valley Wrestling had a tendency to send wrestlers to other promotions, sometimes with the idea the experience would make them wrestle better when they got back, sometimes as a favor to a struggling promotion and sometimes as means of increasing a wrestler's drawing power or getting OVW some extra exposure. Note, this is usually par the course for training facilities and developmental, indeed OVW had done this before its relationship with WWE was even a thing, but still surreal for them to keep up at it after becoming a WWE brand. Some highlights include Carlito Colón's return to WWC, CM Punk's return to RoH and Beth Phoenix showing up at SHIMMER. Even after WWE 'officially' dumped OVW in 2008 they continued to send contracted wrestlers to work there until some time in 2010.
All Japan Pro Wrestling was basically forced by it's television network to have one with then new promotion NOAH, which happened to be taking All Japan's television spot, as a way of establishing NOAH to the former AJPW audience. (It worked, maybe a little too well, as it turned out the large majority of NOAH's audience were only watching it as a continuation of what they though All Japan was and refused to accept new wrestlers). All Japan was in turn forced to bring in most of the Wrestling Association R roster to survive, including previously banned for life Genichiro Tenryu.
CZW used to regularly crossover with Big Japan Pro Wrestling. That was, until a CZW booker walked out of BJPW with one of their titles. Later CZW would establish ties with Ring of Honor and later still, Chikara. CZW has also been invaded by IWA Mid-South and Maven Bentley Productions (the latter seems kind of redundant, as they have almost all the same talent on their rosters anyway).
Ring Of Honor had a quite a few, its Age Of The Fall stable appearing in Full Impact Pro, it housing "SHIMMER matches" including the title defenses. Its "feud" with Combat Zone Wrestling. Featuring stars from Japanese promotion Pro Wrestling NOAH. It has also sent its champions out to defend their belt on the shows of other promotions such as TWC in the UK and "invaded" the Puerto Rican branch of the International Wrestling Association.
Impact Wrestlingused to do crossovers with Ring of Honor and CMLL. They persevered longer doing crossovers with AAA, "team TNA" being a regular fixture there in triple's matches.
Kaiju Big Battel used to have ongoing angles collaborated with Chikara Pro. Two of Chikara's biggest angles, The Order Of The Neo Solar Temple and Die Bruderschaft des Kreuzes only being possible because of this interaction despite most of the wrestlers in both groups have little direct contact with Big Battel itself.
CMLL frequently has them with New Japan Pro-Wrestling, particularly after 2008 and usually benign as sharing of talent can be but their most infamous interaction was in 2005 whena group from NJPW called La Ola Amarilla stormed CMLL and became a regular thorn in the promotion's side since.
In 2005, California based Empire Wrestling Federation met with Ultimate Pro Wrestling and did a joint show to raise money for the areas believed not to have received proper funding following the Hurricane Katrina storm the year prior.
Since 2007, Independent Wrestling Association Texas and Anarchy Championship Wrestling have had quite a few. Many of their shows and even title belts are commonly referred to as IWA Texas ACW: *Insert Here*. Eventually though, "IWA Texas" got dropped and everything became ACW.
In New York City New York, Fighting Spirit Wrestling has a working relationship with predecessor Warriors Of Wrestling and later comer Valkyrie Women's Pro.
Reality show Dana White: Lookin' For A Fight worked with UFC and Jerry Lawler's Memphis Wrestling in 2018 to give us Beale Street Brawl, which featured Derrick King and Matt Sera (with Dana White as their manager) Din Thomas and Dustin Starr (with Maria Starr as their manager).
Believe it or not, even the isolationist WWE has started doing this, with working relationships with promotions like Evolve, which often sees NXT wrestlers perform on Evolve events. This has been both good note Former Evolve guys like Johnny Gargano, Roderick Strong, Adam Cole, Matt Riddle, Kassius Ohno and others return for matches and WWE sponsored their 10th Anniversary Show. and not so good note Often, the NXT guys will win over the Evolve talent, which isn't necessarily bad, but guys like Babatunde or Arturo Ruas who are mid-carders or jobbers-to-the-stars at best, will win over homegrown talent, and Fabian Aichner, who is barely on NXT TV, let alone relevant, actually won the Evolve Title.
National Wrestling Alliance since being bought by Billy Corgan of The Smashing Pumpkins has this as it's hat. When it first started, the World title was defended at numerous independent promotions, with Nick Aldis winning the World title from Tim Storm at a Wrestling/CZW show. This would culminate at a defense at the independent PPV All In, which saw Cody Rhodes win the NWA title. They've also had numerous crossover matches at Ringof HonorPP Vs. Most recently, World Women's Champion Thunder Rosa has defended her title in All Elite Wrestling on TV, as well as challenge for AEW's own Women's title at the PPV All Out in 2020. Currently, the NWA is hosting a weekly series of crossover PP Vs with the United Wrestling Network called Prime Time Live.
The independent PPV All In in 2018 counts as one as well. Ringof Honor, National Wrestling Alliance, and Wrestling/NJPW joined forces with Tony Khan and Cody Rhodes for the world's first non-affiliated pay per view. It drew more than 11,000 fans to the seats, and sparked off what would become All Elite Wrestling in 2019.
WWE and TNA collaborated on a pair of one-nighters in 2012. First TNA employee Ric Flair was allowed to go to WWE for the Hall of Fame induction of Flair's old group The Four Horsemen; WWE subsequently sent Christian the other way for one night at TNA's Slammiversary event.
Mike Awesome appeared on the April 10, 2000 WCW Monday Nitro while still holding the title, Paul Heyman filed an injunction to prevent Awesome from appearing on WCW TV. This led to the one-of-a-kind situation where Tazz, a WWE-contracted wrestler, defeated Awesome, a WCW-contracted wrestler, for the ECW World Heavyweight Title.note 