subscriber (n.)

• almoner
• almsgiver
• angel
• approver
• assignor
• backer
• bestower
• conferrer
• consignor
• contributor
• cosignatory
• cosigner
• donor
• endorser
• giver
• grantor
• guarantor
• insurer
• notary
• party
• patron
• patroness
• philanthropist
• presenter
• ratifier
• settler
• signatory
• supporter
• testate
• testator
• testatrix
• underwriter
• upholder