JabRef
Mendeley
Zotero
Qiqqa
Citavi
Docear
Paperpile
EndNote
I2c
Deferit
Openpay
Bread
Clearly Payments
Clearpay
Humm
QuickFee
Mendeley - Easily organize your papers, read & annotate your PDFs, collaborate in private or open groups, and securely access your research from everywhere.
Deferit - Deferit is a billing and budgeting platform that allows you to pay bills in fortnightly installments and make your budget go the extra distance needed.
Zotero - Zotero is a free, easy-to-use tool to help you collect, organize, cite, and share research.
Openpay - Openpay is a payment gateway solution.
Qiqqa - Qiqqa is a free research and reference management software. It can be used in many organizational projects from the academic to the personal to the business endeavor. Read more about Qiqqa.
Bread - Bread is a buy now and pay later platform that lets you buy things in easy installments.