Having a shower for second baby used to be considered greedy and unacceptable. But now it is not only acceptable, but it is actually necessary for some families to have a baby shower for second baby. Though mom-to-be may already have a lot of major items from her first baby. Crib, stroller, high chair - she will need many other items.
Moms-to-be always need things like diapers and wipes, undershirts, bath accessories, and feeding supplies. Second baby showers could actually be a “sprinkle” shower. A "sprinkle" shower is where guests buy only necessities rather than having a full-blown shower.
You could also consider finding out from mom-to-be what she wished she had but didn’t get first time around. Then add those items to suggested gifts. It could also be a “Bear Necessities” theme decorated with all sorts of bears for shower for second baby.
You could have baby showers for second baby for a caboose baby, or a baby born much later than other babies. Might be very similar to a first time baby shower. Most likely, if there are many years between babies, these parents no longer have any baby items and will be in need of all types of gifts for second baby showers.
For moms-to-be who already have enough for baby, you might consider having a “mom” baby shower where everyone brings a baby shower gift for mom-to-be instead of for baby. These can be items with which she can pamper herself, or items that she may need while she is in labor.
Sometimes mom-to-be doesn’t need anything for baby or for herself, but she wants to have a get together with friends. For this type of party, you may want to ask guests to bring unwrapped baby gifts. You can all wrap these gifts at party, label them, and then donate them to a charity in mom-to-be’s (or baby’s) name.