Well it depends on your needs and preferences…
for me this is what I have and the order I have it
Guitar ->
Tuner pedal – I use the Boss TU3 for its great buffer which is important to preserve your tone when you have a bunch of pedals with true bypass. True Bypass is nice and all but if you have ALL true bypass it will suck your tone out so make sure you have a pedal with a buffer at the beginning and end of your chain.
Wah pedal -> I use the BBE Wah, although any number of options is great here. Teese, Fulltone, Budda, Vox, Dunlop, Xotic all make great wahs
Booster/Preamp pedal -> I use the Dunlop EP101 for this. There’s some great pedals for this. The Keeley Katana and Xotic EP Booster are also some nice alternatives. There’s also Treble Boosters like the Dallas Rangemaster and its clones (Brian May pedals has a few of these).
Overdrive pedal -> there’s SO many overdrive pedals. I personally use the Wampler Euphoria due to its versatility but there’s so many great OD pedals. There’s the Ibanez/Maxon Tubescreamer and Tubescreamer clones like the Seymour Duncan 805 and Wampler Clarksdale, there’s Klon Centaur and Klon clones like the Wampler Tumnus and MXR Sugar Drive, there’s Dumble type overdrives like the Fulltone OCD, Hermida Zendrive and MXR Shinjuku Drive, there’s Chandler Tube Driver types like the MXR FET Driver and Lovepedals Dover Drive etc I can go on and on here
Distortion/Fuzz pedal -> Again, so many choices here. There’s the ‘classic’ hard clip distortions like the Pro Co Rat, Boss SD-1 etc but these days there’s a bunch of ‘amp in a box’ pedals here as well which attempt to duplicate the sounds of the Marshall Plexi (Xotic SL Drive, Lovepedals Purple Plexi, RambleFX Marvel Drive, JHS Charlie Brown etc), Bluesbreaker, Fender Bassman, Fender Deluxe etc Supro even makes a pedal that duplicates their small amp! For Fuzzes there’s generally Fuzz Faces (now made by Dunlop) and Fuzz Face clones (either silicon or germanium), Electro-harmonix Big Muff Pi and Big Muff Pi clones, and Maestro Tone Bender (not made anymore) and Tone Bender clones. I personally use the BBE Windowpane because its a cheap and an effective silicon fuzz clone.
Delay/Flanger/Phaser/other modulation etc -> I put my delay near the end of my chain here though depending on your amp you may choose to run it through the effects loop instead. I found Delay to be the most useful out of the modulation effects. There’s generally three types here, analog delay like the Boss DM-2W I use (Way Huge Aqua Puss, Electro-harmonix Memory man, Maxon AD9 and MXR Carbon Copy are a few other popular analog delays), tape delay like the Maestro Echoplex and its clones (Strymon El Capistan, Keeley Magnetic Echo, Catalinbread Belle Epoch etc), digital delay like the Boss DD-7 etc although some specialists like Catalinbread even try to copy obscure delays like the oil drum and echorec delays
Compressor -> I put my compressor after my delay, some people may put it before. I personally use the Xotic SP Compressor which is a copy of the Ross compressor which is a popular compressor, but the Keeley Compressor, MXR Custom Comp, etc are also popular
Reverb -> This is my second to last effect in my chain and its because I like reverb to apply to everything. Again there’s many reverb types but the most popular reverbs are the Spring Reverbs (Catalinbread Topanga, Hermida Reverb etc), Plate Reverbs (Catalinbread Talisman), Hall/Room Reverbs (Keeley Abbey Chamber) or some combination of those (Keeley Omni Reverb which I use, Keeley Hooke, Digitech Supernatural, TC Electronic Hall of Fame, Electro-Harmonix Holy Grail, Strymon Flint etc)
Looper -> Since I’m a solo guitarists this is pretty necessary for me. If you’re in a band, you might or might not need it. I use the Boss RC-3 looper. The Digitech Jam-man is also pretty popular. In addition, this is the second buffered pedal I use and put it at the end of my chain in order to preserve my highs.
-> Amp