Basically any upbeat song that reminds you to appreciate life in the middle of absorbing and applying theory. Anything from the Internationale to Red Army tunes to modern(ish) artists like Chumbawamba are allowed. Even Lofi.
Personal favorite of mine is Quand Fera-T-Il Jour, Camarade? by Mireille Mathieu. It's bittersweet, hopeful and resolute. Even if I don't speak French, I sometimes mumble to it.
Runner-up would be Solidarity Forever by Pete Seeger.
Quand Fera-T-Il Jour, Camarade is fucking great.
For other upbeat Seeger songs there is "If I had a hammer"
Joe Hill has a lot of bops along with his somber songs: Mr. Block , The Tramp , It's a long way to the soup line , There is power in a union
Billy Bragg: Never cross a picket line, There is power in a union (no connection to the Hill song, instead it has the tune of Rally round the flag) ,
Chumbawamba has a lot of good stuff like you alluded to, I like their Diggers stuff: world turned upside down and Diggers Song Other stuff would be Give the anarchist a cigarette, Land of do what you're told, Enough is enough
There is a fuckload of other ones but that's what I got off the top of my head and from specific places