Hi :)
I am using various solutions to design my kicks:
1) Michigan Synth SY0.5
2) MI Plaits
3) Sometimes using samples but I am not convinced anymore :)
Nevertheless, I am still pursuing the best solution to design my kicks as ready made ones (macro oscillators or other dedicated kick modules) do not offer as much sound design possibilities.
I have been gathering info from YT and I come to the conclusion that I am more enclined to use a basic VCO with various waveforms, an EG (ADSR or ASR) and a VCA to yeld the results I am aiming at.
Here are a couple of resourceful videos in case it can help:
 - The Modular Spaghetti Solutions - Making a Eurorack modular Techno kick drum with an envelope generator. No VCA needed
 - Sinus - Tech Talk 004 Make Your Own Kickdrum In Eurorack Pure Analog Deep Full Live Patching
 - Thomann - How to create the perfect kick drum | Lets Patch | Thomann
 - DJ TechTools - How To Make An Analog Kick with Tobi Neumann
 - Voltage Control Lab - Eurorack Modular Kick Drum Tutorial
 - Stazma - Analog Kick Drum tutorial: Stazma Modular Tips & Tricks