I will freely admit to being a Sentai/Power Rangers fan. I'll also freely admit that some season of Power Rangers are much better than others. I wasn't a fan when the Mighty Morphin' Power Rangers first started back in 1992. When Ninja Storm came on I caught a few episodes but it wasn't until Tommy's return in DinoThunder that I started watching it regularly. Thanks to constant reruns of the series I've been able to watch most of it.
At various places on the internet, people have been doing pixel art of the Power Rangers. One of the more popular templates is Acalt's. Acalt has an archive of the Power Rangers from the various season (as well as the various Super Sentai Rangers). I can take no credit for any of the individual Power Ranger images here, all I did was arrange them. Other (more talented) people like Acatl did the hard part of re-creating the costume designs.
This is a group image of the various Power Rangers from the Power Ranger series from 1992 (Mighty Morphin Power Rangers) to 2009 (Power Rangers RPM).
This is a "scorecard" of the various Power Rangers from the Power Ranger series from 1992 (Mighty Morphin Power Rangers) to 2009 (Power Rangers RPM).