Kotaku Ranked the Tony Hawk games from Worst to Best: https://thebests.kotaku.com/lets-rank-the-tony-hawk-games-from-worst-to-best-1844342766
It's a pretty good listing but I disagree with THPG being lower than THPS HD. That game was a mess.
I also disagree with this statement: "In a lot of ways Pro Skater 4 is just more Pro Skater 3. They look similar, feel nearly the same, and use a lot of the same tricks [...] But as a follow-up to THPS3, it felt a bit too samey and unfocused."
THPS4 was only similar to THPS3 in the sense you still choose a Pro Skater and upgrade their stats. The levels were MASSIVE, layered, and had an entirely different set of objectives. It is known as being the most difficult of the series on Normal settings and was probably the biggest leap and deviation from the formula. Once you beat the game, it opens up into a NG+ will entirely new hardcore difficulty objectives. It's like two full games. Not sure how they landed on it feeling the same.
My Order from Worst to Best:
14/13 - Ride / Shred
12 - Tony Hawk's Pro Skater 5
11- Tony Hawk's Pro Skater HD Remastered
10 - Tony Hawk's Downhill Jam
9 - Tony Hawk's Proving Ground
8 - Tony Hawk's Pro Skater
7 - Tony Hawk's Project 8
6 - Tony Hawk's Underground 2
5 - Tony Hawk's Pro Skater 2
4 - Tony Hawk's Pro Skater 3
3 - Tony Hawk's American Wasteland
2 - Tony Hawk's Pro Skater 4
1 - Tony Hawk's Underground
God I love this series. I'd say they're all good in my list from 10 down. Downhill Jam is actually decently fun but definitely not a Tony Hawk game by any stretch. It's like a knock off SSX or Downhill Domination.
Also the GBA version of Underground and the DS version of American Wasteland (titled: American Sk8Land) are pretty fun too. I think Vicarious Visions made those as well.