Thanks for providing a good way to play old formats. One improvement I think youncould make is by aligning your formats on tcgone with how old formats are played in real life. Here is a blog gaining popularity, revisiting and discussing them: https://jklaczpokemon.wordpress.com
Gen 1 is comprised of (in most playable ):
Base - Jungle
Base - Fossil
Rocket - Neo (Rocket-On)
All of which are quite playable. I witnessed many people playing these formats more specifically than ever at the latest TCG Regionals tournaments in Memphis and St Louis.
At the moment on tcgone, when you click gen1 you get matched with people with other sets. This is problematic when it gets to >30 users.
I think as pokemon is bigger than ever now - it is the largest card game, and old card prices reaching higher prices and harder to find. Your website tcgone is the best way to keep these old formats most accessible. Especially as The Pokemon Company International does not and will probably not recognise old WOTC cards.
Again, thanks for providing this good free site. Hopefully you can promote on reddit .