@akargeOur cheerleaders were self-organized volunteers, pretty much effort of one girl. I don't remember, perhaps didn't ever know, did she succeeded to make it official and lasting (she graduated the same year than me). The sport they cheered on was basketball, possibly even exclusively so, but then, there wasn't much else either.
When I moved to the school for the fifth grade, it was in Soviet Union and remained there for several years still, but when I graduated high school from the same school, it was... not quite in EU and NATO yet, no, but joining both within next ten years was seen as survival dictated goal and practical inevitably.
Back in Soviet Union youth sports were wholly parallel to school system and under wide umbrella of military, although I'm not sure about the status of "prof-tech" vocational sports school(s) that caught international level athletes and future coaches, perhaps it was hybrid under both or something. Otherwise sports that happened in school gyms after hours weren't schools affairs, but facility rentals by sports clubs, while schools employed no coaches beyond PE teachers. I may not have paid attention previously, but only remember school-to-school games after independence, and those weren't fully official either, rather tolerated than administered, and very much unserious, although some got quite invested in those nevertheless of course. To the point a cheerleader team spawned itself.
It was a time when the yearly inflation was 1000% and police refused to react on calls claiming their vehicles are out of fuel, but the life in high school at least and even more generally I'm sure, soldiered on, in hindsight surprisingly normally.
With a tad bit over thousand students in the entire school, first to eleventh (later twelfth, with renumeration happening throughout, as it was zeroth grade made compulsory what triggered it), our school was large by local standards, but not a very large one; there were a few twice that size. Tracking inheritance from the first public school for girls in the city and located in the heart of the old town (with exactly six car parking spaces officially attached) it juggled egalitarian spirit with subtle elitism in undertones eschewing restoration of "gymnasium" moniker in contrast to some others.
There were cliques, just quite different, and changing ones. Jocks? Sure there were some, even though sports not an integral part of school itself, but that community was quite fragmented. Basketball dominated, being very democratic, easy to set up class-vs-class tournaments and similar (think homeroom vs homeroom, only our "homeroom" was a permanent affair fist grade till graduation). Curiously, state politics at one point were dominated by social networks stemming from amateur and college basketball dubbed "basketball mafia." While ice hockey might have more vocal if not necessarily bigger fan base, it didn't manifest in any discernible way in school at all, but football was frowned upon in our school's dominant ultranationalist environment for being too Russian dominated (soccer of course; we would call that game some derivative of rugby it is, and pretty much no-one knows a first thing about American football here anyway, it doesn't exist, neither does baseball by the way).
Politics were hyper important, but our school didn't have Russian flow, so that conflict was absent, at least internally (besides dedicated Russian schools, many nominally Latvian schools had Russian "homerooms" that had their instruction almost exclusively in Russian; ethnic-adjacent political conflict and confrontation was common in such mixed schools, especially at this transitional period.
Instead we had... let's call them "suits" a clique of self-described "future business leaders" who were extremely focused on academic achievement (but often in a cheaty or formal way, without true engagement with the material) and were extremely obnoxious, cynical and snobbish, despite being sneered on by much about anyone else.
While pretty much everyone who mattered in student society was in some way connected to the drama club. The informal, alternative one, not the official one. Neither was actually functional, in terms of staging any production. This networked influence was less strange, if you consider it only mirrored the national resistance movement that was led and populated by poets, writers and artists.
However, the school was taken over by a sophomore gang at one point. Loosely led by six "brothers" it eventually included or at least affiliated about half of that sophomore year, a third of then juniors and many others, even some seventh graders. This non-organization was responsible for well over 80% of all extracurricular activities in the school for next three years, including dance nights that happened so frequently the principal was forced to issue an edict that dances can't happen in two consecutive fridays.
School newspaper wasn't a clique, it was an individual, more or less (for whom it was pocket money business, perhaps more than anything else, pocketing money trickling from Soros fund over a long cascade). And yes, he was a nerd from the same drama club, but was never fully accepted by the "brothers" or invited to their private parties...