My "no, thank you" list:

Non-ferrous frames. Aluminum, titanium, carbon fiber, unobtanium need not apply - I'm just not interested.
Four-arm cranks. Still just plain fugly to my eyes.
E-shifting. Just another thing to go wrong on a ride.
Down tube shifters. Nothing wrong with them, and they make recabllng much less complicated, but I'm a bunch less flexible than I used to be.
Toe clips and straps. Look cool and I rode a pair across the USA (granted, that was 45 years ago), but again, I'm not as flexible as I used to be. Plus, SPDs are a lot more comfortable.
Single-bolt seat posts. I mean, I will if I have to, but they are invariably impossible to set just exactly where I want. I'd much rather wrestle with a traditional Campy 2-bolt (and that really isn't that hard with a 10mm ratcheting wrench, swivel nice but not essential). Nitto Frogs would be ideal if they came in more diameters.
Non-aero brake levers. Because of my decreasing flexibility, I have to be able to brake from the hoods. In my experience, aero levers have better mechanical advantage than non-aero levers, and I want my brakes to work, especially since I'm a big boy who generates a lot momentum on descents. (For the same reason I generally prefer dual pivot brakes, but the Suntour single-pivots I have on one bike do the job just fine - and yes, that bike has aero levers.)
Tubulars. I went away from them in early 1980s, tried them again for Eroica CA about ten years ago. For me, they are no longer worth the hassle, especially since my usually sluggish pace does not give much if any of their advantages, especially since I ride Conti 5000s and rode the 4000s before them.
E-bikes - for now and for the foreseeable future. But as I start my still-early-stage slide into decrepitude, I have to take a "never say never" approach. But the motorcycle-replacement urban terror machines are a non-starter.

My largely but not completely heretical "yes, please" list:

First, the non-heretical ones - Steel frames, preferably lugged or fillet brazed, but nice TIG welds will do in a pinch.
San Marco Rolls saddles, especially the Titanios. They just work for my butt, so I've stopped looking for others. I do have an old Brooks Pro and a NIB B17 in reserve, just in case.

Now for the more sinful stuff - Campy 10sp triple drivetrains. Look good, work well.
SPDs. I have 'em on almost all my bikes and they work great for me.
Tall Nitto stems. I like the Tallux that Rivendell sells (Technomic height, nicer finish).