Once you learn 25 or 6 to 4, it shouldn't be a stretch to add two more to your repertoire. They use the same chord progression.
I played this one 53,697,109 times in my long-time cover band in the '90s. Well, maybe not quite that many times, but it seemed like it.
We've all heard the Zeppelin version enough by now, I'm guessing, so how about this version from Great White? I'm thinking this was MTV Unplugged but don't know for sure.
And, unrelated to the above and just 'cause I love the original Chicago band before they became "smooth pop" or whatever in the '80s, here's a favorite of mine with the late Terry Kath on guitar and vocals.
Guitar geek bonus points for anyone who can identify the guitar riff at 4:39 - 4:43. Hint: it's a "quote" from a song by a popular rock guitarist/singer/songwriter.