Baby brush, baby nail clippers (just used my teeth).
Grobags - DD hates them
Our bath has been brilliant as has our nappy bin, never had an issue with smells.
We have one of those breathing monitors, the breathing sensor part is still in the box... DD is coming up to five months and still in our room anyway in her crib, and we just haven't used it. I don't think it's entirely pointless as in some ways can offer peace of mind and in others can freak you out if they roll off it and set the alarm off.
Baby bjorn bouncer - really dull, DD not interested in it. Thankfully it was leant to us.
Things like jumperoos and playmats I would get second hand, they'll only use them for a few months.
People bought us loads of summer clothes in 3-6 months, which she is now only just big enough for and they aren't the type you can layer up for winter.
Bottle warmer - used twice and then didn't bother.
Pampers newborn - Aldis first two size nappies are just as good and so much cheaper.
Our travel system, bought because it was cheap, wasn't happy with it and ended up buying one second hand for the carrycot which was brilliant for us.