I've been solo several times. I like to eat at Sci-Fi, Boma, Jiko, Sanaa (by the window), Flame Tree Bar B Cue, Coronado Springs food court and LeCellier!
Hi stranger! Haven't seen you on the boards lately.
To OP: I to go to WDW several times a year solo and since I prefer TS over CS have eaten at most WDW restaurants. The only place I would not go back solo is Biergarten. For some strange reason they sat me as the only female at a table with two parties that were all men.

My favorite places to dine solo are Boma, Jiko, Flying Fish, Artist Point, California Grill, Coral Reef, Narcoosee, Citricos, Yachtsman, outside at Big River Grill, outside at Rose & Crown, upstairs by a window at Yak & Yeti, Cape May at dinner, Pepper Market at CSR, WGP Express, and on the covered patio at Turf Club at SSR.
This past Dec I ate dinner at the Garden Grove at the S/D for the first time. I didn't realize it was a character meal on certain nights and just went there for the seafood buffet. The place was empty, food was really good, and the characters really sweet (the waiter threatened Pluto about stealing stuffed lobsters and Pluto pretended like he was stealing mine. Since the restaurant was so empty, the characters all made two rounds so I saw them all twice. The second time around, Pluto took a seat at my table and pretended to eat. I finally shooed him off, telling him I was fine solo.

).