I think my votes go to Mid 80s Audi 5000. Fiat X 1/9s. Anything Ferrari that had urethane-on moldings. The Nissan NV van is just a royal pain due to its size and encapsulation or moldings as are Freightliners. I personally am not a fan of using an Extractor on roofline or post beads.
Tough removals usually occur when design precedes the tools. The raw edge glasses like a VW Eos become much easier with a wire removal system than trying to use a combination of every other older removal tools that a tech had with him.

Ford made it hard in the 80's when it decided to go thin with urethane on Escorts or double dashboard beads on the early Taurus. Equalizer made its mark in tools during this time. The cold knife blades became thinner, sharper and multi-shaped as need adapted.