Besides Sayge and the ticket turn-ins, the Darkmoon Faire has a human cannonball, a tonk battle game and stalls selling food and rare goods. Games and quests also earn tickets. Blizzard's Classic post describes them, and Forever may change the details.
The Humanoid Cannonball
The Blastenheimer 5000 Ultra Cannon fires you toward a target in the water south of the fairground. Hit it for the fun of it, and watch your landing.
Tank Battle Simulator
You take control of a Darkmoon Tonk and destroy Tonk Targets. Engineers can also make a Steam Tonk Controller.
Sayge
Answer two questions for a 2-hour buff, then take a written fortune. See Sayge's buffs.
Food, drink and rare goods
Vendors sell Faire food such as the Darkmoon Dog and Fizzy Faire Drink, and Blizzard says some sell rare items, so check their stock early in the week.
The Jubling pet
Forever's files include an Unhatched Jubling Egg and A Jubling's Tiny Home, which teaches a companion. In the original game this came from a quest at the Faire. We haven't confirmed how it works in Forever.
Should a low-level character go
Yes, if it's your faction's easy week. Sayge's buff helps at any level, and you can hand in low-level trade goods for tickets. Don't make a long trip through high-level zones for it, though. Check the route first.
The full picture is in the Darkmoon Faire guide.
Activities: Blizzard's Darkmoon Faire post. Item names: WoW Forever client 1.60.1 game files, read through wago.tools.