I use IF Marcal in a French/Ligue 1 squad so LB options are very limited but he has been tremendous ever since I picked him up. He is by far the best left back going forward I have ever used because of his combination of pace (which is even better with a shadow chem style), pretty good dribbling, and his absolutely deadly crosses. His shooting isn't half bad either because of his 86 shot power. Defensively he can occasionally be caught out on the counter because of his work rates and poor marking and he also sometimes struggles to bully players off the ball with his low strength. However, with the shadow chem style, he is an excellent tackler which helps make up for his defensive shortcomings. Additionally, he will win most aerial duels he faces which I really appreciate in my fullbacks.
Overall, going forward he is the best left back I've used with better offensive stats than the much more expensive Alex Sandro (who I use in my Serie A team) but he can sometimes disappoint on the defensive end as compared to Sandro or the IF Roussillon.