Some spells have casting times of 1m (Tsunami, Conjure Elementals, etc). I am a low level caster with no access to Wish. Is there a way to prepare the spell (maybe somehow pre-cast it the day before into an item) to be able to use it in combat in a single turn?
If I'm in a defensive position, I can combine a spell with Glyph of Warding. But the Glyph can't move too far, so it won't work if I'm storming the enemy castle and I need my trusty elementals. Spell scrolls and Rings of Spell Storing also maintain the spell's casting time, as far as I know. Sorcerers can only quicken 1 action to 1 bonus action.
What other options are there?