Suggest a small, elegant saddle bag.

[fossyant]

Decathlon do some. I'd recommend some additional Velcro, just in case. They don't strap round the seat post though. I am not having some cheap Velcro rub on my Dura Ace 7400 seat post, no way.

 

[Arjimlad]

We've got that exact one on all our bikes with tube, tools and rubber gloves inside!

I was looking at mine on my bike today and thought it looked pretty smart, actually - could be Giant OEM as the blue on the reflective design is the same as on the bike. Yet to see if it is waterproof at all though !

 

[Hacienda71]

And it falls off too.

 

[172traindriver]

Try this by Lezyne

http://www.lezyne.com/en/products/organizers/caddys#!m-caddy

 

[MikeW-71]

I have one of these:
http://www.evanscycles.com/products/evoc/race-saddle-bag-ec034400

1 tube, patches, multitool, levers. Sorted.