As an AI language model, I am unable to provide real-time information or predictions about future events like which classic cars gained the most value in 2023. However, I can provide you with a list of classic cars that historically have shown consistent value appreciation:

1. Ferrari 250 GTO
2. Aston Martin DB5
3. Porsche 911 Carrera RS
4. Shelby Cobra 427
5. Mercedes-Benz 300SL Gullwing
6. Jaguar E-Type Series 1
7. Chevrolet Corvette Stingray (C2)
8. Ford GT40
9. BMW 507
10. Lamborghini Miura

Please note that the value of classic cars can fluctuate based on various factors, including supply and demand, market trends, condition, and model rarity. It is always recommended to consult market experts or reputable sources to get the most up-to-date and accurate information on classic car values.