Pedals
Overdrive is a must. I love my EHX Crayon as I really like the two EQ controls they help clean up problem frequencies. It completely replaced my BYOC screamer clone on my board. The Wampler Tumnus Deluxe is probably the only pedal that could replace it. For EVH Echoplex preamp or the EXH 5150 OD.
Compressor. Need more sustain on those squealies? Did you already put a brass block on that floyd? Still not enough sustain? You don’t have to be a country chicken picker to have a compressor. Also helps counteract the sustain loss from the noise gate you will invariably need with all these pedals. EHX Tone Corset.
For reverb there are two paths the “I never want to buy another reverb pedal again” so you get the EHX Cathedral, Boss RV-500, or Strymon Big Sky. I’d lean towards the RV-500. For simplicity or pedalboard real estate conservation try the EHX Holy Grail Neo. Personally I’m not a fan of a spring reverb with a distorted shred tone but I need something with a spring setting for when the need to play surf rock arises and a hall setting which is what I prefer for all things metal.
Delay
Like reverb you can go “I want one delay pedal” or get the simplest possible. Boss DD-500 or Strymon TimeLine are the ultimate delays. If you just want analog or tape get the MXR Carbon Copy, Dunlop Echoplex, or Boss Space Echo.
I’d go with the DD 500 since I really like precise tempo setting for playing rounds and fugues.
Looper
This is probably the most overlooked and underappreciated type of pedal but it can help so much with composition and learning licks. I prefer simple for this. For complex stuff I just use a DAW and record stuff. EHX Canyon (can also meet your delay needs), Boss RC-1, TC Ditto.
Phaser
MXR M290 Phase 45. Script setting for the EVH tones, Block setting for the “swooshier” stuff. Set the speed pretty low.
Pitch
Digitech Whammy 5. This is simply one of the most fun pedals out there. Great for experimenting with harmonies. Great for creating pseudo organ sounds with the octave up or down harmonize setting.
Digitech Drop Tuning is really nice for experimenting with tunings on a floyd rose equipped guitar.
Whammy DT if you want both of these. Don’t get a Whammy 4 it isn’t true bypass and it’s a tone black hole.
Noise Gate
ISP Decimator, all the other ones decimate your tone.
Power
MXR DC brick. Voodoo Lab pedal power.
Amps
Do you get decent cleans out of your 6505? I never did. Roland JC-120 or JC-60. Metallica used a JC-120 for “One” and “Fade to Black” Get an amp switcher like a Voodoo Lab Amp Selector. You now have a great palate of sounds.