hitjam.io
A real concert harp, plucked strings that ring on after you let go.
No MIDI keyboard? Play with your computer keys: bottom rows are the lower octave, top rows the higher one. Hold Shift to sustain. ← → octave, ↑ ↓ semitone.
Virtual harp
The notes are recordings of a real concert harp, plucked strings from the deep bass to the bright top, more than six octaves. A harp string keeps ringing after it is plucked, so let your notes overlap: that wash of sound is the harp.
Plug in a controller and run a finger up the white keys for the harp's famous glissando sweep. On letter keys, run along the Q row for the same effect.
No plugin, no sample library and no account. Play it, record it, and keep the WAV, which is made on your own device.