Honestly, he kinda is a meme. I wouldn't recommend any of the movies. It's not like you've missed some grand piece of cinema that you have to be ashamed of and must fix it ASAP. It's the sheer volume of mediocre movies and the very distinct role of a guy who always kicks bad guy's asses using karate in all these movies. I mean, the fact that you've never seen something like Walker, Texas Ranger probably just means that you are under 30 years old, but by no means it's good TV series that everyone must see.
Delta Force is a good movie within the action genre.