We got a new cot bed and mattress because my eldest was still in hers.
Buggy board, but I guess you won't need one given your age gap.
Rain cover for the pram cos ours was all ripped and leaky hah.
New bottles and teats. The bottles we'd used weren't widely available anymore to buy teats easily for them so we got rid and bought a different brand that was easier to find in local shops for replacement teats etc. Same with dummies.
Two sleepytot teddies, picked a different one from eldest's as she still sleeps with hers.
Some new clothes, we kept everything that wasn't stained from eldest but eldest was a summer baby and second baby was autumn, so we needed quite a bit tbh. Mostly layers, sleepsuits and sleeping bags, and scratch mitts.
Formula. Wearable breast pump, didnt have one with first, it was useful with second, did quite a bit more successful pumping and found it more comfortable to use.
A present for my eldest for becoming a big sister. We got her a book called 'Youre the Biggest' and a little toy till as she was interested in tills, money and playing shops at the time, as well as a baby doll baby carrier as she was also into baby dolls. Thought she'd like to use it whilst me or DH had baby in the sling or carrier, and she did.
Dribble bibs, second child was (and still is, at 15 months) a much droolier child than my eldest was!
Baby hair brush. Baby bath. Baby shampoo. Baby oil. Nappies. Changing mat. We got a new changing table for downstairs too as we were using our original one for storage still in eldest's bedroom. New one came with storage boxes for inside the drawers under it too which is all handy.