We recently learned FME is popular within the (commercial) GIS communities. While this is not exactly open source software, there is also Data Exchange for Free and Open Source | Safe Software and Free and Open Source: The Inside Scoop on FME and FOSS | Safe Software.
We learned the most popular open source alternative is GitHub - halestudio/hale: (Spatial) data harmonisation with hale studio (formerly HUMBOLDT Alignment Editor), see also Hale Studio Alternatives and Similar Software - AlternativeTo.net.
An introduction by the author is at https://www.quora.com/What-are-the-open-source-alternatives-to-Spatial-ETL-offered-by-FME-Safe-software. Their forum is available at https://discuss.wetransform.to/.
There are also other FME Alternatives and Similar Software - AlternativeTo.net.
On Write data from grafana in the data source - Grafana Community, we also just found Apache NiFi.