New Sightstones

The addition of support items made the bot lane a lot more diverse, but the options for vision are still pretty lacking. To give incentive for other lanes (and supports that want to build offensively) to build vision beyond spending gold on just wards, there could be three versions of the Sightstone:

1. Lifestone - 150 HP and builds out of a Ruby Crystal.
2. Bladestone - 12 AD and builds out of a Longsword.
3. Magestone - 25 AP and builds out of an Amplifying Tome.

Three versions of Ruby Sightstone:

1. Ruby Lifestone - 400 HP and builds out of a Sightstone and a second Ruby Crystal.
2. Steel Bladestone - 30 AD and builds out of a Bladestone and a second Longsword.
3. Sapphire Magestone - 50 AP and builds out of a Magestone and a second Amp Tome.

Combine costs can be adjusted to have equal gold efficiency, but they're already really close (1060g, 1080g, and 1088g respectively). Gold value for wards is identical for all three, since they'd operate the same way.

Edit: Suggestions from others include a version for attack speed, and a late game version that offers both offense and HP.