Plus like.... If we're talking 5E, the only thing that's debatably unbalanced player race wise is Yuan-Ti and that's due to the whole "resist every magic spell in the game" thing they got going on
What little Con boost you'd get from a dwarf isn't really doing much for a wizard simply due to how 5E's HP system works. See also the "Its more effective to heal people up from unconcious than to do mid-fight healing" deal with 5E.
Yuan Ti aren't exactly busted though (though MMM does nerf them). I mean, Gnomes have advantage on Int/Wis/Cha saves, which includes some of the worst things to fail a save against, and people barely play them as it is.
Having played a Yuan Ti in a campaign, here's what actually happened:
*I encountered few actual spellcasters.
*Often, when I would ask the DM if a monster ability was magic, he'd say no. When pressed on this, he opined that, since there's a total lack of guidance as to what counts as "magic", if he ruled that every preternatural ability enemies had was magical, I would get advantage on most saving throws. As annoying as that was to hear, I couldn't really argue the point, and this seems to be how magic resistance is played at most tables.
*Sometimes even when enemies used spells, they did so through extraordinary means other than traditional spellcasting, which led to a few spirited debates on the subject, lol. We were up against an opponent who could evoke magical effects from candles lit in her chamber, which couldn't be counterspelled; the DM attempted to rule that if counterspell doesn't work, magic resistance shouldn't either, but they eventually recanted after I pointed out my "advantage" hadn't worked on anything the whole game, lol.
*The actual busted ability was immunity to the poisoned condition, because WotC uses it a
lot, even where you wouldn't expect it. For example, the stench of Troglodytes; I was never happier than when I told the DM I was immune to the effect when we had to fight a pack of them (it was a pretty grueling fight because several other characters were being forced to roll at disadvantage).