I haven't been on my trip yet, so I can't give personal reviews, but I've done a ton of research for GF options that I can share!
For table service, maybe not quite half of the restaurants I looked at have an allergy menu. The ones I've considered most for us are Skipper Canteen in MK, Sci Fi Dine-In in HS, Garden Grill in EPCOT, and Sebastian's Bistro and Steakhouse 71 in the resorts.
For quick service, I can share my list of the park restaurants that offer mobile ordering that have GF menus. I've only finished two of the parks so far, but will edit when I do the others.
Magic Kingdom
Columbia Harbor House: GF: salmon or shrimp with rice & green beans, chicken strips and fries
Location: Liberty Square near Haunted Mansion and not far from Fantasyland
Cosmic Rays: GF: cheeseburger or hot dog, fries, Greek salad
Location: right after you cross the Tomorrowland bridge
Pecos Bills: GF: beef/chicken nachos, chicken/pork rice bowl
Location: before the turn toward Splash/Thunder coming from Liberty Square
Pinocchio Village Haus: GF: pizzas and chicken nuggets
Location: Fantasyland across from carousel
Hollywood Studios
Backlot Express: GF: cheeseburger, chicken strips, or southwest chicken salad
Location: near Indiana Jones and Star Tours, middle area
Catalina Eddies: GF: chicken caesar salad and pizza
Location: Sunset Blvd near rock n rollercoaster
Woody's Lunchbox: GF: BBQ brisket or chicken salad sandwiches, tomato soup
Location: Toy Story land
ABC Commissary: GF: chicken club sandwich, plant based burger, steak fries, mediterranean salad
Location: direct back of the middle area
Docking Bay: GF: beef and chicken bowls with rice and interesting sauces, interesting salad, tuna poke
Location: deep in Star Wars land near Smuggler's Run
Dockside Diner: GF: shrimp salad roll or chipotle chicken roll
Location: on the lake in the middle
Fairfax Fare: GF: california BLT hot dog, regular hot dog, hot dog salad
Location: Sunset Blvd near rock n rollercoaster
PizzeRizzo: GF: antipasto salad with ham & salami, pizza
Location: Grand Avenue (before Star Wars world) near MuppetVision
Ronto Roasters: GF: breakfast wraps served without wraps, pork wrap without wrap for lunch/dinner
Location: Star Wars world