Depends on how you want to define custom. If by custom you mean any board, whether it be a complete custom from a GB or just a board you made from mass produced parts, then no it’s long gone. My first build was tray mount 60% in a plastic case which quickly got upgraded to a low profile aluminum case, then rebuilt a couple times, eventually getting disassembled to recoup the parts. If by custom you mean a fully custom board from a GB that has proprietary parts, then yes I still have mine. It would be a Redscarf II+ ver.C kit I bought from someone on mechmarket around 3 yrs ago. I very rarely use it anymore as I have much better feeling/sounding boards, but as it was my first true custom in my eyes I want to hold onto it.
Most of my starter boards & tray mount 60%s I built to try out different switches I have sold off though. I encourage anyone in this hobby to sell a board they have stopped using for the most part & don’t have any particular attachment to for funding future builds. As long as you ain’t trying to scalp on the prices it’s a win win, someone gets a new board so it’ll be used frequently again & you get funds for stuff you’d rather have than that/those boards. Also given the huge money sink this hobby can be when you get into the higher end stuff it only makes sense to sell some boards to fund future ones IMHO.