A 36-pack box gives you 12 spare packs
Spreading menace counters across subtypes is a pretty mediocre mana investment without a meaningful payoff
The ability won't affect those spells and it won't affect spells that those players cast before you activated it
If you are playing with just Tales of Middle Earth cards, you will probably want to cut The Balrog, Flame of Udun because of the density of legendary creatures in the set, especially with the ring tempts you mechanic making any creature legendary
Secret Lair x Post Malone: Backstage Pass Zur the Enchanter From the Secret Lair x Post Malone: Backstage Pass comes Zur the Enchanter, reimagined as Post the Enchanter
Finally, we have Dolmen Gate, arguably one of the best cards in the deck next to Species Specialist, because when we attack, our creatures cant be dealt combat damage, so our Horde can attack with impunity (unless our opponents have removal spells or abilities)