I was stunned to find in Wikipedia, these islands are are "in" the Thames.
Isle of Sheppey
Two Tree Island
Canvey Island
Lower Horse Island
Frog Island, Rainham
Chiswick Eyot, Chiswick
Oliver's Island,
Kew
Brentford Ait, Brentford
Lot's Ait, Brentford
Isleworth Ait,
Isleworth
Corporation Island, Richmond
Glover's Island, Twickenham
Eel Pie Island, Twickenham
Swan Island, Twickenham
Trowlock Island, Teddington
Steven's Eyot, Kingston upon Thames
Raven's Ait, Kingston upon Thames/Surbiton
Boyle Farm Island, Thames Ditton
Thames Ditton Island, Thames Ditton
Ash Island, East Molesey
Tagg's Island, Hampton Court
Garrick's Ait, Hampton
Benn's Island, Hampton
Platts Eyot, Hampton
Grand Junction Isle, Sunbury
Sunbury Court Island, Sunbury
Rivermead Island, Sunbury
Sunbury Lock Ait, Walton on Thames
Wheatley's Ait, Lower Sunbury
Desborough Island, Shepperton
D'Oyly Carte Island, Weybridge
Lock Island, Shepperton
Hamhaugh Island, Shepperton
Pharaoh's Island, Shepperton
Penton Hook Island, Laleham
Church Island, Staines
Hollyhock Island, Staines
Holm Island, Staines
The Island, Hythe End
Magna Carta Island, Runnymede
Pats Croft Eyot, Runnymede
Friary Island, Wraysbury
Friday Island, Old Windsor
Ham Island, Old Windsor
Lion Island, Old Windsor
Sumptermead Ait, Datchet
Romney Island, Windsor
Black Potts Ait, Windsor
Cutlers Ait, Windsor
Firework Ait, Windsor
Deadwater Ait, Windsor
Baths Island, Eton
Wick
Bush Ait, Windsor
Queen's Eyot, Dorney
Monkey Island, Bray
Pigeonhill Eyot, Bray
Headpile Eyot, Bray
Guards Club Island, Maidenhead
Bridge Eyot, Maidenhead
Grass Eyot, Maidenhead
Ray Mill Island, Maidenhead
Boulter's Island, Maidenhead
Glen Island, Maidenhead
Bavin's Gulls, Maidenhead
Formosa Island, Cookham
Gibraltar Islands, Marlow
Temple Mill Island, Hurley
Frog Mill Ait, Hurley
Black Boy Island, Hurley
Magpie Island, Medmenham
Temple Island, Henley-on-Thames
Rod Eyot, Henley-on-Thames
Ferry Eyot, Wargrave
I guess I've been on about 10 of them - used to have a tiny Avon boat when I lived in Weybridge near the D'Oyly Carte Island (Gilbert & Sullivan) - Carte with a macabre sense of humour kept a crocodile there.
Here's Mrs. Cazalea driving us along near Hampton Court in an electric boat.