Yes, pgrep and pkill originally come from Solaris. If anyone cares about the history here, they were added by Mike Shapiro in Solaris 7 to speed boot time -- he discovered that there were a ton of RC scripts that were doing "ps -el | grep foo | grep -v grep", and he was able to shave significant boot time by distilling this into one command. (pgrep and pkill both originated with this work; in as much as they had direct inspiration elsewhere, it was from the "slay" command found in QNX.)

If my long-windedness can be excused, a pgrep anecdote that I feel must be told: when Mike was originally doing pgrep and pkill, he wanted one to be able to search on every field specified in proc(4), including the wchan (denoted by pr_wchan), an archaic field that was actually a stowaway from Multics (!). Even by Solaris 7, the wchan had no real significance in Unix, and the co-inventor of /proc, Roger Faulkner, flew into an indignant rage that Mike would include it -- and "pgrep -w" quickly disappeared from both Mike's workspace and his PSARC case. Now, Mike and I were also the gatekeepers on Solaris 7, and we both wore pagers (aside: I'm old) that would page us whenever anyone integrated anything into Solaris with the bug synopsis. Sometime after pgrep/pkill integrated into Solaris 7, I decided to screw with Mike a little: he was headed to watch a Boston Celtics playoff game, and I knew he would be away from a machine for a few hours, so I started paging him with fake integrations that I knew would enrage him. The first integration that I fooled him with was someone that he disliked rewriting a command that Mike himself had just taken from the same engineer and himself rewritten -- and I really tweaked him by making the synopsis be that the "error messages could be improved" (trust me that this was a sore point). Now, I wanted the fake integrations to get more and more absurd over the course of the playoff game, so I next paged him with an integration from Roger: "pgrep(1) needs to be able to search on wchan". I was just getting ready to send my next page (after all, I had a couple hours of mischief planned) when Mike suddenly appeared in my office, drenched with sweat, panting "please just tell me the first one was a joke too!" As it turns out, he had taken my first page a little too seriously, had immediately stopped watching the playoff game, got back in his car and was returning to work to "throw [disliked engineer]'s monitor out his office window." When he saw the wchan option to pgrep, he knew that I must be screwing with him, and fortunately stopped at my office before doing anyone (or anything) physical harm. And that's how "pgrep -w" saved a monitor -- if not a life.