MBP (2016) to Thunderbolt Display with Thunderbolt 3 (USB-C) to Thunderbolt 2 Adapter and extension cable I have a MBP15 (2016) and connected it to my Thunderbolt Display via the official [Thunderbolt 3 (USB-C) to Thunderbolt 2 Adapter]. but the cable is too short for my needs right now. I tried 3 different Extension Cables (1, 2, 3) but none of them worked (no image on the screen). Is there a cable that works? If not possible is there a dock that can do this?
Sure. Any thunderbolt 3 or 2 dock will work. Be sure to read the friendly manual - not all cables that fit physically in a thunderbolt slot are thunderbolt cables and cables can be faulty.
I’ve only seen 10 foot 2 cables in copper. You’ll need optical to go further and they are pricey but very long range. Two feet is the longest 3 cable I’ve seen.

https://www.amazon.com/Cable-Matters-Certified-Thunderbolt-Black/dp/B01AKP8Z4C
https://www.monoprice.com/product?p_id=24721
https://www.owcdigital.com/products/thunderbolt-3-dock-14-port