[Sticky] Parts for urgent review

[Tim Gould]

I've made this a sticky thread. Please add parts whose absence makes a major gap in the library. Try to stick to older parts (more than 1 year on the PT) but if a new part is important and appears to be overlooked (eg. new basics like tiles, plates and bricks) add it too.

And for those who wish to help review but don't know how, try this tutorial.

For example:

The 4.5V and 12V have been on the PT for a long time.