Neoprene ankle cuffs; https://www.wiggle.co.uk/gripgrab-cyclingaiter/
My latest attempt to keep my feet dry- Tried dry suit cuffs, waterproof socks, can’t get on with waterproof trousers on the bike etc. These are simple and did well in a torrential downpour for an hour or so last week. The water will get in eventually but its all about tipping the balance in dryness’ favour! Would like something that goes up the shin a bit for all the spray from puddle soakings.