Conjug. Stem Ch. V PrSimple
There are mainly three changes, not considering u-ue as only the verb jugar is in this category: Yo jUEgo, Tú jUEgas, etc.
e-ie sEntir sIEnto
e-i repEtir repIto
o-ue llOver llUEve
Remember that in the Present Simple Tense, verbs don't go through stem changes when conjugated with the first person plural 'nosotros'