Your emergency stasis kit should ideally have syringes (preferably large and small for feeding critical care or liquid food), Fine Grind Critical Care by Oxbow Health, perhaps some baby gas drops (sometimes gas pains can be related to stasis) usually people recommend simethicone drops (I haven't personally needed this, maybe others can comment on a specific type of brand?).
Your kit could also include other things that may be useful in day to day/normal situations such as cotton buds (people usually use for cleaning scent glands), a pair of nail trimmers (rounded cat ones so the nail doesn't break), styptic powder or pen (used on the nail as sometimes when cutting too far it can bleed, the powder just stops the bleeding) and finally which ever grooming brush/brushes you use, if you don't have any I've seen people use flea combs, the furminator, the fur buster or even just your hands to pull out the jellyfish furs, and finally you could keep a bag of treats in the kit as sometimes you may need to bribe your bun. Some people keep thermometers but personally I don't (maybe another user can comment on the use of those?) And in the summer you could keep some mite serum to apply so if your bun/buns go outside there is a lesser risk of mites (this may not be necessary if your vet gives mite treatment)
Finally make sure you have a carrier that is suitable for your bun/buns, if you'd like to you could even put a fleece or blanket and a toy inside so in the future all you need is some hay and your buns and you are ready to go! Hope this helps <3
Myself also have different tools to pluck ticks in my kit and for wound cleaning. I also have ready made saline solution. It’s something I often use for my bunnies plus the things the other have already covered