"What sockets are compatible with FCPGA988 sockets?"
Hmmm... How about PGA988?
If you are thinking that you can upgrade your Ivy Bridge processor to something modern, you cannot.
The i7-7700HQ uses a bga socket, which means it is soldered to the motherboard.
Why do you not tell us what you want to accomplish? Perhaps then we can help.
For an upgrade processor, which would not be worth it for an Ivy Bridge processor (in my opinion) such as yours, the upgrade processor must be socket, BIOS, and chipset compatible.
You would need to ask the system/motherboard manufacturer what processors are compatible with their bios. And, that is only possible if the processor is not soldered to the board.
Forget all of this, and get a new(er) machine.