Walker gets one in the pilot episode. Three guys who raped a young circus performer have come to Walker's ranch—where the girl and her two co-performers are staying for safety—and proceed to chase the girl in an attempt to kidnap her. Walker shows up and, well, ass gets kicked. Then we get this gem from the thugs' leader, with Walker's response:
Leader: You screwed up, Ranger. You forgot to read us our rights!
Walker: You're right. You have the right... (kicks leader in the face, knocking him down) ...to remain silent.
In the Children of Halloween, we see Walker singlehandedly fighting a cult of torch-wielding satanists. He goes after the leader, who attempts to stab him, but ends up stabbing himself accidentally. The following sort of borders onto Nightmare Fuel when we see (possibly from the Leader's point of view) fire and then we hear laughter.
When Trivette's cousin dies in suspicious circumstances, he and Walker discover the man had stumbled upon his commander at a local army base stealing arms for a racist militia group. Trivette has the man at gunpoint, the guy spitting at him and Walker has to stop Trivette from shooting him as "not worth it."
The man's followers then take over a local news station where Alex is a guest and demand their leader be released. Walker stages a one-man invasion of the place, taking down terrorists left and right, including tricking one into setting off a bomb that send the guy flying out a window.
Trivette shows his own grit confronting the man who killed his cousin and taking him down in a lopsided fight.
The big finale has Walker personally taking down the leader in a one-on-one showdown, kicking the guy through the control room window. Better yet, it's all caught on live TV so the onlookers at C.D.'s grill cheer him on.
And Walker tops it all off by doing a speech on how America is built on all races and trying to push anyone down is totally un-American, getting a standing ovation from the grill onlookers.
Any time Walker has to deal with Victor LaRue. Period.
''The Trial of LaRue" has Walker finally gunning Victor down.
"The Avenger" is a particularly notable episode, because Walker is forced into a series of Vietnam-themed death matches by a fellow 'Nam war veteran, Caleb Hooks, out of vengeance for killing his brother, Randall, in a standoff. These fights are much more creative and intense than the usual fare of beat 'em ups (fighting in total darkness, over Punji stakes with katanas, and inside an electric cage with mechanical torches) and they eventually lead up to a dramatic knifefight with Hooks himself.
Walker's battle with Philippe Brouchard is one of the very few fights in the series where someone is on equal standing with his caliber of skill. It plays out like a genuine fight for one's life instead of the usual Curbstomp Battle, similar to Die Hard in some respects (the bad guy hides his identity and holds a building hostage).
Walker facing off against the Viper, a very high-profile assassin who has killed 12 people and is working on number 13, the President of the United States, and apparently holds a connection to the John F. Kennedy assassination. His presence raises questions about what actually happened that day.
C.D.'s showdown with the Hangman, the serial killer that caused him so much emotional grief it made him retire as a Texas Ranger. He never bagged the killer because he disappeared from the streets after being checked into a mental institution. They tried and failed to rehabilitate his issues with women because of an abusive mother. Though C.D. has grown old and a little slower, he's still very capable of doing his job.
Walker's final battle with Emile Lavocat, revealed to be C.D. Parker's killer.
The Season 5 finale "The Wedding: Part 1" sees a one-shot character named Kim Rivers (a friend of Alex) getting into a scuffle with a female member of a group of hitmen that started shooting during her wedding ceremony; finishing with Kim saying "This is for ruining my wedding" before knocking the assailant out. Keep in mind during this fight Kim was still in her wedding dress.
How the villain in "Warriors" is killed: He's lit on fire, then Walker kicks him out the window, where he falls onto some flammables and explodes. Can't get much more over-the-top than that. Scene.