Apart from mustard and cress...

[tectonicplates]

Are there any other small plants I could grow on a windowsill, on tissues/kitchen paper, without soil?

Bearing in mind that a lot of seed companies are really busy right now so they might have sold out!

Food plants I mean, not flowers.

Beansprouts.

rocket, basil and coriander

dried peas

Pea shoots are easy and really tasty!

you can grow peas for peashoots and sprout a lot of seeds such as broccoli, alfalfa, linseed and they are very tasty & nutrious. Still lots for sale on ebay

I think you might need a tray with some compost for the dried peas - they usually sell it in supermarkets so it might be available at some point but it worth having a go with kitchen paper. Our local primary used to grow the Tesco value ones into pea shoots.

I have grown the whole coriander seed before from the spice aisle.

Chia seeds. Tastes of more when sprouts than seeds.

Back in the day, we used to grow mung bean shoots in a jar, with a piece of muslin over the top attached with a rubber band. Rinse daily.

I think some pulses (like red kidney beans) can be a bit iffy (the ones that need 10 minutes fast boiling?)