This is a true-bypass relay bypass kit for your DIY pedals. It has EQD-style hold functionality, optional optocoupler muting, and more.
See more details here: https://mas-effects.com/relay-bypass/
Base price includes PCB with pre-assembled SMD components, and a pre-programmed ATtiny microcontroller (IC).
For a few dollars more you can add the rest of the parts to build this (note the first two may be hard to find):
- Voltage regulator
Build docs here: https://mas-effects.com/relay.pdf
You can find a cheaper PCB+IC combo for earlier versions (v1, v2) here. Complete kits for v1 and v2 are sold out though.