BBM issued 35 sets in 2017 (including a couple that were actually issued in late 2016). This may sound like a lot but it's actually the fewest number of sets they've released in a year since 2009 when I think they issued 34.
21 of these sets were BBM's perennial sets - the "flagship" 1st and 2nd Version sets, the high end Genesis set, the 12 pack based team sets, the Rookie Edition (draft pick) set, the "Farewell" set for players who retired in 2016, the Rookie Edition Premium set, the two dance team/cheerleader sets ("Hana" and "Mai") and the "Icons" box set (which had a theme of "Japan Pride" this year).
There are a couple of other sets that look like they will become annual issues. BBM released the "Fusion" set for the second consecutive year which is kind of a wrap up on the season - it includes cards of player highlights and the statistical leaders as well as additional "flagship" cards and more First Pitch Ceremony cards. The "Time Travel" set has replaced the annual "Historic Collection" set and the 2017 edition set highlighted the year 1975. BBM issued their first ultra high end set since 2015's "Masters Of Insert" - this one was called "Rising Sun" and featured active players instead of OB players. BBM also issued another multi-sport set to follow up on 2016's "Masterpiece" set - this one was called "Infinity".
For the fourth consecutive year, BBM issued a box set a specific team's cheerleaders and dance squad. This time around it was called "Fighters Girl & B * B Family" and (obviously) was for the Fighters squad (and mascots).
I was a bit disappointed this year that BBM did not issue a "Classic" set. I'm guessing that it simply wasn't popular enough to continue after four years.
The remaining nine sets were all team specific box sets. Most of these featured autograph or memorabilia chase cards. There were "Premium" sets issued for the 2016 pennant winners (the Fighters and the Carp); "HEAT" sets issued for the Dragons, Tigers and Lions and "Young" sets for the Carp, Tigers and Fighters. There was also a box set issued called "Successful Achievement" that celebrated the Carp winning the Central League pennant for the second year in a row. (And yes, you're reading all of this correctly - there were three box sets issued for the Carp and two each issued for the Fighters and Tigers. The nine box sets covered only five teams.)
Other than the Time Travel set there were no OB only sets issued this year (although the Fusion set had a number of OB players in it). I'll be curious to see if there are more OB sets issued in 2018 as there are a number of team anniversaries this year that were commemorated in sets in 2008 - the Hawks franchise founding (80th in 2018), Lotte acquiring the Orions (50th in 2018), the Whales moving to Yokohama (40th in 2018) and Seibu acquiring the Lions and moving them to Tokorozawa (happened in 1979 so 2018 is the Lions 40th season in Saitama). There also were no "single player" sets issued this season for the first time in quite a while.