HGACBuy is a nationwide, government procurement service.
www.hgacbuy.org
BuyBoard
https://www.buyboard.com
TXMAS (Texas Multiple Award Schedule Contracts)
http://www.window.state.tx.us/procurement/prog/txmas/
Texas Term Contracts
http://www.window.state.tx.us/procurement/contracts/gci/760-A1.php
Sourcewell
https://www.sourcewell-mn.gov/