Here are some rough targets for the main tire groups.
Formula Cars (IndyCar, FX, FA, FR3.5): 1.7bar front / 1.45bar rear (24psi / 21psi) at road circuits. The Dallara IR-12 oval/speedway tires like up to 45psi on the right side.
Modern GT & LMP: ~1.8bar front and rear. Maybe down to 1.6bar for a very slow track like Long Beach or higher to 1.90-1.95bar at Le Mans to squeeze a little bit more off the rolling resistance.
Touring cars & V8 Supercar: 2.0-2.15bar front and rear
Ford Fusion: 2.4-2.6bar front and rear for road courses. Ovals might go to 3.0bar+ (45-50psi) on the right side
Light sportscars (Radical, BAC, KTM, etc): ~1.6bar (24psi)
Road car tires: All in the 2.1-2.2bar (29-32psi) range hot. Any MotorTrend readers will know how much they stop every few laps and bleed pressure to hold that target during the BDC tests.
Vintage GT: Roughly the same range as modern GT
Vintage Group 6 & Formula: Bit more flexible here. Something in the 1.7bar (25psi) range is usually a good starting point up to 2.0bar (29psi) or down to 1.2bar (17psi) to adjust for balance on something wild like the Lotus 72D