B.E.S. + R.B.

R.B. meshes well with B.E.S. both due to being Machine types, and due to not requiring a Normal Summon at any point, which prevents them from clashing with Boss Rush.

R.B. combos get you to an end board with at least Shepherd, Next Phase, Barricadeborg Blocker and the ability to revive Ga10 Cutter on the opponent's turn (so a Spell/Trap negate plus the Monster negate from Next Phase). 

R.B. combos can be started with Stage Landing, Funk Dock or any 2 Machine monsters and will net the same end result. Getting 2 Machines on the field can be done using R.B. maindeck monsters, Boss on Parade (summon Vic Viper from deck to your field), B.E.S. Dellinger Core summoning itself, Big Core MK-3 or Blaster Cannon Core special summoning themselves if your opponent controls a monster, etc. Avoid using your Normal Summon at all costs. If you're forced to Normal Summon, you should be able to place at least 1 copy of Boss Rush by banishing Boss on Parade from your GY without having to activate Boss Rush manually.

Clockwork Knight summoned during the R.B. combos can send Boss on Parade to the GY to grab Clockwork Night. Boss on Parade can then banish from GY to get hold of a copy of Boss Rush. This is safe to do at any point after Funk Dock summons an R.B. monster from deck and can be done with a second Clockwork Knight while Link climing if you didn't activate it initially.

Barricadeborg Blocker protects your face up spells from destruction. This includes Boss Rush, Boss on Parade, B.E.F. Zelos and Clockwork Night. This is especially useful for B.E.F. Zelos because it in turn protects your B.E.S. monsters.

During your turn you can use Super B.E.S. Metal Slave summoned from your hand to destroy your own B.E.S. monster plus one other card. The best targets for this going first are Boss on Parade if Clockwork Knight didn't send it already (to get another Boss Rush) or your own R.B. Shepherd's Crook, which can avoid destruction using Stage Landing in the GY. Doing this will destroy your B.E.S. monster, thus triggering any copies of Boss Rush you control (generally around 2+ copies at this point). With B.E.S. Metal Slave already on the field you can use this to summon Dellinger and another monster. Dellinger can then revive a monster on your opponents turn, giving Metal Slave up to 4 destruction interrupts (once per chain).

Union Activation can send A-Assault Core from the hand or deck to the GY to search for B.E.S. Dellinger Core. This can alternatively be swapped out for 3 Pot of Extravagance. Most Extra Deck monsters should only need to be summoned once so you will likely not affect your combo, however Clockwork Knight may be an exception.

Combo examples:

Combo 1:
- Activate R.B. Funk Dock. Search R.B. Stage Landing. (Optional step if you already have Stage Landing in hand.)

- Activate Stage Landing and Special Summon R.B. The Brute Blues.

- Activate Blues to search R.B. Ga10 Cutter. (Search Funk Dock instead if you started with Stage Landing. Funk Dock can search Cutter.)

- Special Summon Cutter. (You can now summon non-R.B. monsters without disrupting anything.)

- Link Summon R.B. VALCan Booster. Search R.B. Stage Landing.

- Activate R.B. Stage Landing to summon an R.B. monster from deck.

- Activate R.B. VALCan Booster to revive Cutter.

- Link Summon Clockwork Knight using Cutter. Send Boss on Parade to search Clockwork Night if it is already face up and you have used both effects.

- Activate Knight and tribute the other R.B. monster to revive Cutter. This will trigger Funk Dock to summon another R.B. monster from the deck. (B.E.F. Zelos can safely replace R.B. Funk Dock.)

- Link Summon R.B. Shepherd's Crook using Clockwork Knight and R.B. VALCan Booster.

- Activate Shepherd and set R.B. Next Phase from your Deck or GY.

- Link Summon Barricadeborg Blocker using the two R.B. monsters. (Use this opportunity to discard a card if you need to.)

- Proceed with B.E.S. related cards and effects.

Combo 2:

- Start by controlling any 2 Machine monsters.

- Link Summon R.B. VALCan Booster using the 2 monsters. Activate its effect to search for R.B. Funk Dock.

- Activate R.B. Funk Dock and search for R.B. Stage Landing.

- Activate R.B. Stage Landing and Special Summon R.B. Ga10 Cutter from your deck.

- Link Summon Clockwork Knight using Cutter.

- Activate VALCan Booster and revive Cutter.

- Link Summon R.B. The Brute Blues using Cutter and VALCan Booster. 

- Activate Blues and search R.B. Stage Landing.

- Activate Stage Landing and Special Summon VALCan Booster from your extra deck.

- Activate Knight and tribute Blues to revive Cutter. This will trigger Funk Dock to summon another R.B. monster from the deck.

- Link Summon R.B. Shepherd's Crook using Clockwork Knight and R.B. VALCan Booster.

- Activate Shepherd and set R.B. Next Phase from your Deck or GY.

- Link Summon Barricadeborg Blocker using the two R.B. monsters. (Use this opportunity to discard a card if you need to.)

- Proceed with B.E.S. related cards and effects.