A couple of days ago I got the usual notification of a lot of packages pending updates, after pamac crashing during the first attempt, as happens here and there, I was stuck with the “waiting for another package manager to quit” error that I could not solve by deleting the db.lck lock file.
Being the “do random crap” person that I am, I decided to kill pamac-daemon.
Which interestingly solved the issue since now neither pamac nor pacman show any updates pending anymore, even after a reboot. (though installing and removing software does workwith both now)
Naturally I would like to know where those updates went and find out if I fundamentally broke updating packages somehow and/or if that is recoverable.
Check if you are up to date, but I suspect you aren’t:
grep 'RELEASE' /etc/lsb-release
Also check the latest entries in /var/log/pacman.log.
Never kill the daemon. The gui (“pamac-manager”) might crash but the daemon will continue in the background. That is the only thing not turning pamac into a complete disaster.
Now you might be in a partial update state. Hard to tell. You can run update with pacman for a good measure.
sudo pacman -Syu
You might also try
sudo pacman -Qk 2>/dev/null | grep -v ' 0 missing files'
If it does not come up empty, reinstall what shows up in the list.
Comes back with DISTRIB_RELEASE=“26.1.1” which I do believe is up to date.
The pacman.log does not show anything out of the ordinary. Just looks like the log would have after an update anyway. (wait could it have continued updating even though the GUI crashed?)
Very much noted.
Just comes up with there is nothing to do.
Does not come up with anything either.
It is indeed. So you should be good-to-go as long as everything works. 
Indeed. So you managed to kill it after it was finished. Lucky coincidence. That is why the rule is, if the gui crashes - wait a bit more before restarting for the daemon to finish the job in the background.
Yes the GUI is merely the interface. The background process does the job, and unlike the GUI it does not crash (never did for me in over 6 years on 3 different systems). Well you decided to kill it because it told you to keep waiting. If you had waited a bit longer the newly started GUI eventually connects to the daemon process again, such that one can see the further progress 
Impatience breeds broken systems.
Gui stuff to be avoided always where possible.