If you're seeking a RingleDingle alternative, CelebrateAlly could be a good choice. This AI-powered celebration planning assistant offers custom ideas for birthdays, anniversaries and other occasions. It offers tools to draft personalized messages, plan romantic dates and suggest gifts. It's geared more toward planning and ideas than toward creating cards, but it can help spark ideas for your own words.
Another tool you might find useful is Canva. The online graphic design service lets you create professional-looking designs with a range of templates and other tools. It's geared more toward general design than toward personalized greeting cards, but it has AI-powered tools to generate copy and edit photos that could be useful for creating your own custom illustrations or poems. Canva also supports real-time collaboration and offers different pricing tiers depending on your needs.