Lip fillers that work best to pass “the kiss test”, or essentially ones that have a natural look and feel, are hyaluronic acid fillers such as Juvederm and Restylane. While there may initially be a few days of swelling, the result of Juvederm and Restylane to the lips is very natural looking and feeling when it is properly injected.
Another option to consider is fat injections. These can also pass the kiss test, but should only be performed by a highly experienced cosmetic surgeon. And the fat must be taken from your own body, so that can be a downside. However, fat injections can be permanent when done properly, so that is something to consider.
It’s best to stay away from fillers such as Radiesse, Sculptra, or collagens. Collagen is hard to find these days, and the other two are just not meant for the lips.