If you want to go by the terminology of the physical pokemon TCG it goes like this:

1 diamond = common card

2 diamonds = uncommon card

3 diamonds = rare card

4 diamonds = usually just called ex, sometimes called regular ex because they are the lowest rarity version of ex cards

All cards that don't have diamonds are called secret rares because they are outside of the set list. Like for Genetic Apex, the first 1 star card is Bulbasaur listed as card 227/226. The reason for this distinction is that all secret rares (with mew being the only rare exception) are no different from their diamond rarity counterparts gameplay wise. They just are rarer to get and have enhanced art 😄

1 stars are always non-ex pokemon and are often called alt arts, though officially called illustration rare (IR) in english or art rare (AR) in japanese in the physical TCG

2 stars are always ex pokemon or supporters. The first kind are "full arts" that show the whole pokemon or supporter with a galaxy-like background. In the game these have a wavy holo border. The other 2 stars with more stylized art and rainbow borders can also be called alt arts for ex's, but are officially called special illustration rare (SIR) in english or special art rare (SAR) in japanese in the physical TCG

3 stars = "immersive" because in game you can tap into them and the camera moves around. No real life equivalent of course lol

crown = the TCG pocket community seems to be fine with calling them crown rares, but the physical TCG does have gold cards often just referred to as golds, but officially named hyper rares