I’m working on a new DM screen, and one thing I decided is that I’d like to have the average stats for each monster type on there, to make improvising monster stats faster and easier if I need to. You could combine this with something like Monster Manual On A Business Card to quickly create a monster; you can use these stats as their saving throws while taking the to-hit and spell save DC from MMoaBC, for example.
You can also use these with something like MCDM’s Minion rules to quickly come up with minions for your battle. Suddenly need a horde of monstrosities to attack your players, but don’t have time to flip to the Chimera to alter it? Just look at the Monstrosities average stats on your screen!
Some monster types (like celestials, fey, ooze etc.) lack large representation in the Monster Manual; if someone can provide a spreadsheet with all the available 5e monsters (which probably isn’t strictly legal to distribute), I’d love to update this to be accurate!
I also have provided only modifiers instead of concrete stats, to save both space and to provide for more ambiguity between individual monsters. IMO it isn’t relevant if the average stat is a 12 or 13, what matters is that both are +1.
Without further ado:
Aberration: +2 +2 +2 0 0 0
Beast: +1 +1 +1 -4 0 -3
Celestial: +5 +4 +5 +3 +4 +5
Construct: +2 +1 +2 -2 -1 +2
Dragon: +6 0 +5 +2 +1 +3
Elemental: +2 +1 +3 -1 0 0
Fey: 0 +2 +1 +1 +1 +2
Fiend: +3 +2 +3 +1 +1 +2
Giant: +6 0 +4 -1 0 0
Humanoid: +1 +1 +1 +1 0 +1 0
Monstrosity: +4 +1 +3 -2 +1 -1
Ooze: +2 -3 +3 -5 -2 -5
Plant: 0 -2 +1 -2 -1 -3
Undead: +1 +2 +2 0 +1 +1
Hope this helps your game!