There are a number of Gachas at Jinx with animesh creatures. Some of these gachas can also be bought as a full set. You can also source second-hand pieces from the gacha on MP where people may sell their unwanted wins.
Some of the gachas have the option to exchange uncommons, rares, or ultra rares for copy versions. This option was only introduced in Aug 2019, so gachas from before that date do not have the option for exchange. This is because the items require a special script inside them to function with the exchange system. If the gacha has exchange option it will say on the vendor picture. If it doesn’t say – it doesn’t have the option of exchange.