[Den-O]

Ranger or sometimes "renger" has been in use since Goranger in 1975. There's a gap from '75 with Goranger until 1989 when the term was used again for Turboranger, then again 3 years later for Zyuranger.

So the term has been in use WELL before Power Rangers made it a thing. Though not as frequently. The term being used in Power Rangers comes from Ranger being used in the Zyuranger source material. NOT the other way around. The majority of teams since then having Ranger or "ger" in their name could possibly have been a reverse influence of power rangers but in all honesty it's easier to just name teams that way too.

In any case the shows that use the term "ranger" or the shortened root of the word for team names are:

Full Ranger
Goranger
Turboranger
Zyuranger
Dairanger
Kakuranger
Ohranger
Carranger
Megaranger
Timeranger
Hurricanger
Abaranger
Dekaranger
Magiranger
Gekiranger

Suffix only
Boukenger
Go-Onger
Shinkenger
Goseiger
Gokaiger
Kyoryuger
ToQger

Frankly the term ranger is extrememly stale with names. I wish they'd move past even using the "ger" on the end of names and do truly creative stuff again like Gingaman, GoGoV, Dynaman, Battle Fever, etc.