Hey, It's That Guy!: Its not uncommon to see the same actor in more than one show playing a different character each time, since Toei usually hire most of their actors from the Japan Action Enterprise (formerly the Japan Action Club) for Super Sentai and other tokusatsu shows. Notable examples include:
Zyuden Sentai Kyoryuger had not one, but two of its auxiliary rangers played by returning actors: Masayuki Teai, who was Eiji Takaoka/Bouken Silver in Gogo Sentai Boukenger, plays both incarnations of Kyoryu Gray (Tessai and his descendant Shinya Tsukouchi), while Ayumi Kinoshita, who was Marika Reimon/Deka Yellow in Tokusou Sentai Dekaranger, plays Nobuharu's sister Yuko Fukui, who eventually inherits the Kyoryu Cyan mantle from Ramirez (himself played by the Canadian-born Robert Baldwin, who was Sazer Gordo in the Toho-produced Chousei Kantai Sazer X).
And on the other side of the coin, Shinkenger has Romi Paku voicing one of the villains. How Toei was able to pull this off, we'll never know.
Shinkenger isn't the first time Toei used high-profile anime voice actors in their Super Sentai series. For example, there's Hikaru Midorikawa voicing Top Galer the pterosaur mecha from Abaranger and Akira Ishida voicing Bae from Gekiranger.
Sandaaru of Hurricaneger (and, by extension, Sandaaru, Jr. in Gokaiger) was voiced by Shuichi Ikeda.
Name's the Same: Counting only the on-duty Rangers, so far we had four Akiras (Goranger, Denziman - this one was a woman - Maskman, and Tokkyuger), two Asukas (Hurricanegernote Shurikenger's real name was Asuka Kagura and Abaranger), two Dais (Flashman, and the future team of Kyoryuger from their reunion special), two Daichis (JAKQ and Turboranger), two Daigos (Dairanger and Kyoryuger), two Daigoros (Goranger and Denziman), two Gais (Jetman and Gokaiger), two Gakus (Fiveman and Gaoranger), two Goros (JAKQ and Ohranger), three Hikarus (Bioman - this one too was a girl - , Gingaman and Magiranger), two Juns (one male in Denziman, one female in Bioman), two Kais (Gaoranger and Magiranger), two Kens (Fiveman and Gekiranger), two Kentas (Maskman and Megaranger), two Kyosukes (Battle Fever J and Carranger), two Rikis (Turboranger and Ohranger), three Ryus (JAKQ, Dynaman and Jetman), two Shiros (Battle Fever J and Bioman), two Shous (Changeman and Go Go V), two Takerus (Maskman and Shinkenger), two Tatsuyas (Denziman and Timeranger), two Yosukes (Dynaman and Hurricanger), and two Yokos (Carranger and Go-Busters).
By extension, one can also count two Dans (Dynaman, as Hokuto/Dyna Red's surname, and Zyuranger where it's Tricera Ranger's only name), two Hayates (Changeman - in which case it's Shou/Change Griffin's surname - and Gingaman - where it's a given name), two Tsubasas (Changeman - again where it's a surname, Mai/Change Phoenix's - and Magiranger, where it's a given name), two Shiraishis (Kensaku/Battle Cossack in Battle Fever and Mako/ShinkenPink in Shinkenger), two Nagisas (Maria/Miss America II in Battle Fever and Sayaka/Change Mermaid in Changeman, also it's not spelled with the same Kanji), two Akagis (Denziman and Akibaranger), three Joes (Liveman - where it was spelled the Japanese way, Jou - Go-onger, a surname also spelled the Japanese way, and Gokaiger - where it's spelled the English way), two Jins (Battle Fever J and Go-Busters), two Kaguras (Hurricanegernote Again, Shurikenger's case and Tokkyuger) and six Hoshikawas (semi-justified: one of them is Ryu/DynaBlack from Dynaman, while the others are the all-sibling team of Fivemen).
In addition, the carrier mecha from Maskman was called the Turboranger (although the pronunciation is different; the Maskman carrier is pronounced "Turbo Runger"), while the evil sentai from Fiveman was called Gingaman.
Two Pink Ranger names have come close: Pink Five (Bioman) and Five Pink (Fiveman).
No Export for You: A few countries have received some form of export of the series, but most of those countries are still missing some of them. North America, for example, has Power Rangers, but that only adapts the series from Zyuranger forward. And even then, people who want the original Japanese shows in countries where Power Rangers is shown are usually out of luck, since Super Sentai is expensive to be licensed in any country, except in Hong Kong, Taiwan and South Korea.