The top two both look like Heuchera 'Red Spangles' - the yellow leaved one could be any of several yellow leaved forms - things like the colour of the underside of the leaf and the flower colour determine which one it might be.

I think the first one could be Firefly, one of the older Heucheras. The other 2 I have no idea.

Ask Google for Bressingham hybrid and have a look at the pictures .I wonder if the coral flowers ( the second one ) may be that.

I think there is one called Lime Ricky..wonder if that is the last one? ..I have one of the other red ones,but didn't know about Firefly,so assumed it was Red spangles..I have had it years,so it could possibly be Firefly then..sorry,Gee ,not much help am I ? :o)
maybe you could look on Vicky's blogs,of Plant a go go ,she has lots on there....one posted January 2010...I have it on my favourites..

The last one looks like my Lime Marmalade 1

Is there not a Lime Marmalade and a Limey Rickey, when it comes to lime ones?

Yellow leaved varieties include: Citronelle, Electric Lime, Delta Dawn, Stoplight, Sunspot, Pistache, Lemon Blush, Key Lime Pie to name a few... and that's not counting the yellow leaved ones with different colour veining...

Phew, I've just spent a very pleasant couple of hours following up all your suggestions and each one I look at I think 'yes, that's it'! I have 4 of the green ones, all quite small still so I will wait and see how they develop. The lime one has now developed a stem with white flowers but it seems that Lime Rickey and Lime Marmalade have white flowers too. The leaves are exactly the same back and front. My new Key Lime Pie has pink flowers.

I bought them as 'pot luck' heucheras and they were just roots! Can't remember what I paid but there were supposed to be 6 in the packet and I ended up with 8 or 9 pieces.

Thank you all for helping out. I have enjoyed following up your suggestions and spent ages looking at Vicky's photos and blogs (thanks Bloomer for pointing me there), wonderful collection and just made me add more to my wish list :)

It's quite staggering how many varieties of Heuchera there are now - it also seems many nurseries breed their own selection, which is probably why there are so many different names for what might, in fact, be the same, or very similar, plants.

No problem,Gee...hope I'm not persuading you to part with more money ! :o)

I've got some vouchers, Bloomer, so it doesn't seem like spending money :)

Lucky you,I have none left..love receiving them for gifts instead of presents :o)