Carbonyl condensation reactions involve carbonyl components and undergo nucleophilic addition and alpha-substitution steps. One component, which is the nucleophilic donor, is converted into an ENOLATE in the presence of base and undergoes an alpha-substitution reaction by reacting with another carbonyl compound which behaves as the electrophile.
Although commonly observed in undergraduate chemistry, carbonyl condensation reactions are not restricted to aldehydes and ketones, but include esters, amides, acid anhydrides, thiol esters and nitriles.
Here are a list of carbonyl condensation reactions you can choose to look at: