The NBA had a record number of free agents this year. Well over 40% of the league was a FA. Many signed 2+ year deals and in two years the 2021 class should be loaded again. But next year's crop looks terrible. Draymond Green signed an extension and Caris Lavert just signed with Brooklyn too. Most of the top FAs are older next year.

PG
Kyle Lowry, Jeff Teague, Goran Dragic and Reggie Jackson are the top guys with only Lowry being a stud and he'll be 34 next year. His understudy in Fred VanVleet had a nice post season but he's small and not sure is a true #1 PG. Can shoot the ball well.

SG
Eric Gordan and DeMar Derozan and both will be 31. There is depth to this list and specialists like Joe Harris but no stars.

SF
Gordon Hayward has a player option but I don't know if he would opt out unless he rebounds in a big way. Otto Porter Jr is an option but last year was his best at 17.5 ppg. Danilo Gallinari is here too.

PF
Anthony Davis is the monster with a player option but most expect him to return to LA.
Old vets in Paul Millsap, Ibaka and Favors (he'll only be 29) are on a solid list. Montrezl Harrell is a younger guy too.

C
Andre Drummond will likely be one of the most sought after players as he has a player option. Elite rebounder, good athlete and can switch out on defense. Led all centers by far in steals. Still does not posses an offensive game outside of offensive rebounding and pick and rolls. Would he get over $30M in a light class?
Hassan Whiteside and an aging Marc Gasol will also hit FA.

So that list is really weak. If you want to improve in the next off season it's going to have to be through the draft, trade or internal development. Very weak FA class. Pistons could use a PG and instead will hope Reggie Jackson stays healthy and maybe they re-sign him for a little cheaper.

There are restricted free agents out there in Jaylen Brown, Buddy Heild, Brandon Ingram and Domantis Sabonis.