I'm not sure if your asking for brand suggestions or not. To get a truer color when glueing the glass as opposed to making something to hang in a window, you will want the most opaque glass you can find. All or most companies make both opaque and transparent glass. But, as you can see below, you can still use the opaque glass, you may just need to do things to preserve the color. Some choices are painting the back of the glass (try using silver, white or a shade of the glass). I considered this for the table I just finished because the only gold glass I could find was transparent. I decided against painting the back of the glass because I was afraid I would scratch the paint from nipping and it was such a large project. Instead, I decided to use thinset on the project since the thinset is white, I thought it would do fine ~ which, for the most part, it did. Unfortunately, when the thinset dried, it cracked and can be seen under the amber glass. This picture was taken before I cleaned up the tiles so excuse the thinset on the tops of the tiles.

You can clearly see the cracked glue under the gold tiles, but in the end it was a non-issue and is only noticeable upon real close inspection.

So, you just need to use trial and error when using transparent glass and sometimes the end result can be quite unique or choose the most opaque glass you can find.

Good luck with your projects!

You can also use brite back tape-it is a foil tape that sticks to the back of the glass so the background doesnt show thru. I think someone had found a foil tape at the hardware store also. The foil reflects back thru the glass and is very lovely. There is also opaque glass as mentioned above and vitreous glass tiles and mirror glass. The choices are many so there is no need to restrict yourself. You can also paint the background you are glueing on white.