Zardnaar
Legend
That's why it is more important to know what the DM is actually having come up in the campaign than it is to know whats in the books - because there only being a few cases of Intelligence saves in the book has no bearing at all on how often they will come up in the campaign.
Iknowthatbuttheplayershavemoreorlessfiguredouthowbadintellig
I know that but they players have figured out how bad intelligence is in 5E, its the ultimate dump stat unless you are a wizard, Arcane Trickster or Eldritch Knight.
There are what 2 Monsters (3?) in the MM with intelligence saves and only 1 spell off the top of my head with intelligence saves. This means those classes with good intelligence saves for all intents and purposes only have 1 good save short of a Mindflayer campaign using feeblemind. You are almost better off multiclassing into a Rogue as a fighter for better saves as con saves are very common (poison, spells, concentration) and there are a few strength saves around as well. Same thing for Druids and Wizards if you do not mind losing a spellcaster level or were thinking of MCing anyway.
And since so many saves are wis/dex/con they may as well have gone with fort/ref/will saves.