Dear M. Francesca,

The type of questions you are asking bring with them an implication that venial sin has no effect on us or is not important to our spiritual life. Let's refresh our memories on what venial or
non-mortal sin is from the Catechism of the Catholic Church:

1863 Venial sin weakens charity; it manifests a disordered affection for created goods; it impedes the soul's progress in the exercise of the virtues and the practice of the moral good; it merits temporal punishment. Deliberate and unrepented venial sin disposes us little by little to commit mortal sin. However venial sin does not break the covenant with God. With God's grace it is humanly reparable.

"Venial sin does not deprive the sinner of sanctifying grace, friendship with God, charity, and consequently eternal happiness."

Blessed John Paul II

While he is in the flesh, man cannot help but have at least some light sins. But do not despise these sins which we call "light": if you take them for light when you weigh them, tremble when you count them.
A number of light objects makes a great mass; a number of drops fills a river; a number of grains makes a heap. What then is our hope? Above all, Confession.

St. Augustine

1857 For a sin to be mortal, three conditions must together be met: "Mortal sin is sin whose object is grave matter and which is also committed with full knowledge and deliberate consent."

I don't think the Church has a list of mortal sins that fall under the title of grave matter, but I may be wrong.

As a lay Catholic, trying to represent the Church's teachings correctly, it would be imprudent for me to say that any sin is not a grave matter. If you are not sure whether a sin is grave matter or not, I would talk to your Confessor about the sin at your next Confession.

Mike