Inspired by This answer I’ve written the following code that work for the checkbox as well:
import streamlit as st
# create a function that sets the value in state back to an empty list
def clear_all():
for i in selections:
st.session_state[f'checkbox{i}'] = False
return
st.title("Clear multiselect with stateful button")
selections = ["a","b","c","d"]
for i in selections:
st.checkbox(i, value=False, key=f'checkbox{i}')
# check state
st.session_state
#create your button to clear the state of the checkboxes
st.button("Clear all", on_click=clear_all)