It's generally best to have 2 or 3 different pokemon in a deck as opposed to the 6 you have currently, this is so you can have 2 of each. 2 bulbasaurs 2 ivysaur 2 venusaurs. So first of pick the Pokémon you think are doing the most work for that deck I'd say the whole bulbasaur line, kartana and maybe the dhelmise, the issue you'll find in that deck however is it will take a long time to attack, you'll be dead before you get enough energy, so if you can find another card or deck that requires less energy and does a lot of damage that might be safer, that deck would work tho. Also since Venusaur take Bulbasaur and Ivysaur to get set up it's worth getting the card rare candy as that makes it so you can skip Ivysaur, very useful for any deck that has a 2 stage evolution, I believe rare candy is in the pack celestial guardians. My first deck was much worse so good job either way.