SM.79
The SM.79 Sparviero (Sparrowhawk) was a tri-engine bomber that featured an all metal structure and a unique design that earned it the nickname "hunchback". It was a great medium bomber for the RA in WW2 and excelled greatly at torpedo bombing missions. At the beginning of the war it was known to be "invulnerable" because it was quite fast and it was also a well built plane.
SM.81
The SM.81 Pipistrello (bat) was the predecessor to the SM.79. It was the first three engined bomber/transport in the RA and was used throughout the entire war. It was quite fast and had great range to carry out long missions. It's speed however ended up not being enough as the war progressed and made it an easy target for anti-aircraft and enemy fighters. It was eventually relegated to second line duties of various tasks since the SM.79 surpassed it in the bomber role.
Fiat
Br.20
The Fiat Br.20 Cicogna (Stork) was a low wing twin engine medium bomber. It was the first all-metal Italian bomber and was regarded as one of the most modern at the time of its creation. At the beginning of WW2 it was Italy's main medium bomber but even then it was showing its' age. By '42 it was being used as a maritime patrol aircraft or a trainer for bomber crews. It was much less powerful than the SM.79 considering it had two engines opposed to the Sparviero's three therefore, the SM.79 was liked more by bomber crews.
CANT
Z.1007
The CANT Z.1007 Alcione (Kingfisher) was a three engined medium bomber that was wooden in structure. It had great flying characteristics and was also very stable. It was regarded by some as Italy's finest bomber of WW2. But the fact it was made from wood caused it to be less durable than its counterparts. It had a tendency to get damaged from the harsh desert climates of North Africa and steppes of Russia. The engines were also underpowered so it suffered from a bad engine to power ratio.