Randomly thought to weigh my repair kit. 454g!
(╯°□°)╯︵ ┻━┻
Lezyne Caddy Sack Medium 41g
Continental Race 28 tyre 105g
Birzman 20 Mini Tool 165g
Park Tool levers x2 26g (13g ea)
Lezyne Alloy Drive Co2 50g
Lezyne Co2 cartridge 59g (16grams)
Few misc repair patches
Let me preempt trite replies by saying you shouldn't go lightweight on your repair kit.
Okay, now. How do we go lightweight on the repair kit

The Birzman tool and Caddy shack are two obvious candidates. Definitely don't need all those tools, some of them are for truing wheels and chain repair. Fine for longer rides, but for most stuff where I'm not too far from home I'd just call for a lift if a chain or wheel went. The Caddy shack is pretty beefy and tough, waterproof. That can go. Saved for longer wet rides or touring or whatever. Still want something that holds it's shape though. So no, don't want some wanky 2p sock you found in a charity shop that'll 'do the job'
The tyre can maybe can get replaced with a light version, which I've got sitting around the house I think. The Co2 stuff.. maybe there's lighter options on the market.