There's not much happening in the third-party app integration space for Tumblr besides the existing share buttons. XKit, the biggest extension for Tumblr, halte

There's not much happening in the third-party app integration space for Tumblr besides the existing share buttons. XKit, the biggest extension for Tumblr, halted development after the developer affectionately known as "the XKit guy" was publicly and falsely accused of some sort of harassment over Tumblr. A different, unrelated team has forked and resumed work on the extension.