WiseStamp - WiseStamp allows you to easily create and implement slick and unique email signatures for your business.
Donorhut - Donorhut offers cloud fundraising software for charities and non-profits of any size.
NEWOLDSTAMP - Email signature generator
Txt2Give - Txt2Give helps churches, non-profits, schools, alumni associations, and political campaigns receive donations with text messages.
Sigstr - Email signature marketing
Little Green Light - Illuminating Data. Advancing Nonprofits.