Ardour now comes with the following plugins as part of a standard installation:

a-Amplifier

A versatile ±20dB multichannel amplifier

a-Compressor

A side-chain enabled compressor with the usual controls. Comes in stereo and mono versions

a-Delay

A basic single-tap delay line, with tempo sync

a-EQ

A nice sounding 4-band parametric EQ with shelves

a-Fluid Synth

Wraps the Fluidsynth SoundFont2 synthesis engine as a new sample player

a-High/Low Pass Filter

Independent high and low pass filters with steepness up to 48dB/octave

a-Inline Scope

A mixer strip inline waveform display

a-Inline Spectrogram

A mixer strip inline specturm display

a-MIDI Monitor

A mixer strip inline display to show recent MIDI events

a-Reverb

A reverb that finds a balance between sounding good, using a lot of CPU and having too many controls