Pretty much anything that was samey old BS.
Games with a bit of a "spark", some effort put into the way they look, play, are plotted etc, continue to be quite playable and transcend the era in which they were made and the hardware they used, and can even have a certain charm if the poor graphics and sound are used in a stylistic manner. Hence how I can still happily play stuff like Stunt Car Racer, F19, Civilisation, Monkey Island, Sonic 1, Lemmings...
Those which didn't and were just churned out as yet-another-version-of-X tweaked to fit inside certain HW limitations come off worse. Endless, usually quite ugly and unresponsive bloody platformers or puzzle games... ugh. Too many to try naming them.
Though also, on the whole, pre-true-3D driving and flying games tend to suck. The jerky, unrealistic 2.5D visuals just kill the whole affair. Any F1 game before the groundbreaking Geoff Crammond one, for example, or bike game which used a similar visual conceit. Flight games really suffered badly - have you SEEN the attempt at putting F15 Strike Eagle on the NES?
A few came off OK, but then they satisfied the rule given above e.g. the Rally game on the GameGear 4-in-1 cart is easily the most charming and fun 2.5D race title, just edging out Buggy Boy and Lotus Turbo; it craps all over any pre-Sega Rally "serious" title of the sort; various Space Harrier type flying games are about as realistic as a wacky waving inflatable arm flailing tube man with a celebrity's face stuck on, but they make it fun (and Desert Strike cheated by using a heli and isometric view). The rest just die a horrible horrible death of advanced ageing.
If I wasn't so tired and flu'd up I'd be tempted to roll thru my emulator cart/disk list and come up with some real howlers. But for now, all I can think of is Transbot on the Master System and Transformers on the NES. Christ. Terrible examples of the cheap cash-in platformer/scrolling shooter genre which did nothing to hide or work with the limited hardware.