Steakhouse provides financial services to Maker, ENS, and Lido. They have been active in Maker governance for quite some time. DYOR.
Karpatkey is a spin-out from Gnosis. I assume you know Gnosis and their suit of products. Gnosis is also one of the larger stETH holders and a close partner. Karpatkey was their internal treasury management team that did a good enough job to set out independently. DYOR.
The others are contributors to the protocol or have been actively conversing with contributors over a long period.