Off the top of my head process hacker lets you look up opened process handles, procexp doesnt let you list them, only do a global search for particular one. You need a separate command line handle.exe.

View, show lower pane. View, Lower pane, Handles (or dlls, your choice)

So its hidden under its own separate sub view instead of process properties like everything else, ok. Which handles are inheritable?

I don't understand the question, likely because I'm not a programmer. Do you mean handle types it represents, or does it show handles from sub-processes? I've found the content to be the same as I get from handle.exe from Russinovich. So using handle -s to get a summary, my system shows this - I would think all would be represented in Procexp:

C:\WINDOWS\system32>handle -s

Nthandle v4.21 - Handle viewer Copyright (C) 1997-2018 Mark Russinovich Sysinternals - www.sysinternals.com

Handle type summary: ALPC Port : 1437 Composition : 19 CoreMessaging : 10 Desktop : 16 Directory : 100 DxgkSharedResource: 2 DxgkSharedSyncObject: 1 EtwConsumer : 1 EtwRegistration : 1012 Event : 3591 File : 889 FilterCommunicationPort: 8 FilterConnectionPort: 9 IoCompletion : 1429 IoCompletionReserve: 63 IRTimer : 123 Job : 229 Key : 808 Mutant : 61 Partition : 3 PcwObject : 4 Process : 2540 RawInputManager : 63 Section : 1705 Semaphore : 1512 Session : 56 SymbolicLink : 369 Thread : 734 Timer : 81 TmRm : 26 TmTm : 13 Token : 979 TpWorkerFactory : 61 WaitCompletionPacket: 1846 WindowStation : 22 Total handles: 19822