Some simple LV2 plugin written in C. I used plugins examples from https://lv2plug.in to have a template. These plugins are released under GPL V3 licence.

At this time, there isn't global building. You need to go into each plugin directory and do

./waf configure
./waf build

you can also install plugin, but i didn't tested this part

./waf install

It's just an echo effect with time and feedback parameter. Time controls delay between repetition and feedback controls how repetitions decrease (higher feedback mean lower decrease).

block diagram :

It's a tremolo with a sinusoidal envelop. It have two parameter, rate and depth.

block diagram :

A chorus effect with three parameters ; rate, depth and mix. A sinusoid is used for the modulation.

block diagram :

A flanger effect with four parameters : rate, depth, feedback and mix. The LFO generate a sinusoïd.

block diagram :