Most of (what we call) Linux OSes are formally GNU/Linux. GnuCash is as close as it gets to "made for Linux". If you don't want an accounting-specific application, but just generic spreadsheets, check out LibreOffice.

I highly recommend GnuCash for accounting though: a fellow board member cleaned up an org's accounting by putting it all in GnuCash, where it was a bunch of error-prone Excel sheets before. That really made it easier to keep track and to do it right.