Fruity Delay Bank works much like the Filters 1-3 of Sytrus.It is a multibank (8 bank) digital delay. The Grain section is its most interesting feature, which no other delay in FL has. This option gives it a uniquely digital "Grain Delay" sound. It is somewhat like a bitcrushing sound, in that it makes the delay sound like a retro computer pushed to its limits.
I will be using this plugin regularly now because of the Grain section. Digital artifact-type sounds are important to my music.
Compare Fruity Delay Bank with Hardcore
Hardcore is a pedal emulation plugin which can work as a multibank (4 bank) delay. However, its customization options are very limited. This is not really a competitor of Fruity Delay Bank.
Compare Fruity Delay Bank with Fruity Delay 1-3
Fruity Delay 1-3 are single bank delays.
I think Fruity Delay Bank contains all features of Fruity Delay 1-2.
Fruity Delay Bank lacks various features of Fruity Delay 3: the tone knob, distortion/limiting/saturation, modulation, smoothing, diffusion, and pitch options. Interestingly, the manual of Fruity Delay 3 describes it as an analog delay. I consider Fruity Delay 3 a digital delay with advanced effects options, not an analog delay. I say this because Fruity Delay 3 does not emulate any specific analog delay.
You can mimic the distortion of Fruity Delay 3 using a send (or Patcher), feeding your dry signal to a distortion plugin such as Distructor, and feeding the distortion plugin output to the input of Fruity Delay Bank. You can also mimic the limiting effect using a limiter after Fruity Delay 3's output. This is not an exact replication because Fruity Delay 3's distortion/limiting is in the feedback loop (I think).
Because you can chain single bank delays to get a multibank delay, I think the difference between Fruity Delay 3 and Fruity Delay Bank really comes down to: do you need the grain option of Fruity Delay Bank?
Compare Fruity Delay Bank with Ableton Grain Delay
https://www.soundonsound.com/techniques/ableton-live-grain-delay
I think Ableton Grain Delay is the most famous grain delay plugin.
I think Fruity Delay Bank lacks the pitch/time jitter (randomization) options of Ableton Grain Delay. However, you can create a perception of a pitch drop in Fruity Delay Bank by increasing the "Div" grain value. You could mimic the randomness using an LFO such as Fruity Envelope Controller or Fruity Peak Controller.
Ableton Grain Delay is a single bank delay, rather than multibank like Fruity Delay Bank.