Reshiboar: Yeah, Bad Boar or RDL (if you want to toss in energies to actually use it).
Tyram: Like BM said, Flare Destroy could be an option, or take early prizes to deny them setup, or use certain techs, or (crappy idea but it works) get the right amount of damage to outrage
The outrage way is easier than it sounds, as you can up-damage with Afterburner.
MewBox: LZ a Pluff (or Cinno) as quick as possible, then get out a Muk to stall if you so desire. Yanmega is an option to Linear Attack their Solosis before they evolve them. Pretty much an auto-win for Mew.
ZPST: Try and screw up Goth's setup (donking is so easy. T1 DCE + PlusPower for the Outrage donk) or try to get the correct amount of damage on Zek to Outrage to OHKO Goth - again, crappy idea.
MagneBoar: Magnezone, RDL, Bad Boar. Pretty easy matchup since you can actually OHKO Goth.
Stage 1's: Like BM said, running Mew is an option. Also, simply outspeeding and destroying setup.
As other decks go...
Donphan/Dragons: Outspeed or get correct amount of damage on Dragons
The Truth: I honestly have no idea.
MegaZone: Try to snipe their setup early with Yanmega or just Lost Burn for massive damage and OHKO their Goth.
Techs: DCL is a tech that I have tried in DnD, but I guess it could work in other dechs that play Rainbow. Simply manipulate damage on their side to take prizes. preferably KOing their Reuniclus or Goths. Magby is a good option, basically to up the damage on Goth. Works well in most decks, honestly, as it's easily splashable. Bellsprout is something I've tried before, works better than Magby IMO, as it can let you KO those key Reuniclus off their bench. Gives you trouble if they have more than one Reuni benched though.
Black Belt is an option, but against extremely skilled Goth players they will just feed you prizes to nullify it's usage. Mew is another good idea, especially if you already run Cinno or something that can get 70 damage for little energy.