This adult VPI Caramel Albino Sumatran Short-Tailed Python was the most valuable snake in my collection (~$2500), but I just sold her. But she’s still here, so it counts.
My female Argentine Boa Constrictor is probably pretty valuable now that she is huge and proven. I saw a similar female go for $2000 recently. I spent $150 on her as a baby 8 years ago! I also have a Bell Snow Splash KSB who is pretty valuable.