Watch (and copy) Francis Preve’s approach to simulate a 303 inside Serum.
Percussion Synthesizer is inspired by the Korg ER-1 synth part from BasicHumanTastes and is a free M4L patch.
Native Instruments offer a ton of sounds (2000) and instruments (Synths, Smaples Instruments) plus an organizer app (Komplete Kontrol) for free. Download here.
Francis Preve explains how to use Ableton’s Simpler to create your own wavetables in this article.