Editing Warhammer 40,000/9th Edition Tactics/Space Marines (section)

=====Specific Mixes=====
Specific combinations are mainly dependent on your chapter trait but there are some combo's that are great for any army some examples are shown below:

*Grav-Bomb, stick some grav-cannon devastators or grav-centurions in a razorback, stormraven or rhino with a captain. Yeet it up the board ideally keeping out of LOS or at least partially obscured, then drop off your devastators or centurions in cover somewhere just in range of a nasty enemy unit ideally a centrepiece unit with a high armour save (at least 3+). Then drop the 1cp  stratagem to re-roll all wounds and damage rolls for the unit and if your using devastators use the armorium cherub too. That's 4 shots each at strength 5 AP -3, hitting on 3+ rerolling 1's and re-rolling all wounds and damage rolls. Usually this is enough to make targeting your devastators a priority for your opponent and in all likelihood they're going to take heavy casualties but the unit will have easily made back its points by then and seriously disrupted your opponents army.
**If you're Iron hands or a successor then you can move these guys without any penalty to hit and re-roll 1's without a captain so that's something to consider, only works in the devastator doctrine though.
**Effective against hordes as well so this combo is still good against swarm lists and those army's will have a hard time dislodging your guy's from a ruin. 
*Captain and hellblasters, pretty self explanatory stick a bare bones captain near a 10 man squad of hellblasters and fire on overcharged with only a 1 in 36 chance of dying each time you fire, generally works best if you use a impulsor as this allows you to move a fair distance BEFORE DISEMBARKING to shoot with no penalty to hit, if you're within 15" then that's 20 shots at s8 AP-4 which is enough to cripple or kill almost anything without an invulnerable save.
**Although this unit is a serious threat to your opponent it's unlikely to be killed off early, an impulsor's fairly tough anyway if you give it the shield dome equipment and hide it behind a wall it becomes incredibly difficult to remove turn 1. Not to mention that if you have the right threat saturation in your army then your opponent is unlikely to shoot this thing anyway.
*Aggressor auspex scan, when playing against an opponent like daemons, orks or tyranids it's pretty common to have a swarm of infantry pop up to charge you out of deepstrike, ordinarily this can be a real problem as many of the units available to these armies have ways of getting a very easy charge. This trick's for just such a situation. When you deploy your units leave a nice gap behind your lines where an enemy infantry unit could deepstrike just in range of your agressors ideally a unit of six that hasn't moved, when your opponent tries to deepstrike his infantry play the 1CP stratagem to shoot all your aggressors at his guys TWICE at a -1 penalty, (you should have a chapter master in range anyway so that's not too big a deal) even with a 5 man aggressor unit you should annihilate any light infantry that tries to deepstrike for just 1 cp.
**With iron hands chapter tactic then you can pretty much get the same effect on normal overwatch, for 1CP you overwatch on a 4+, 75% accuracy near a chapter master.
* Gravis Bombs (all types). Can be done with any chapter really, even Forge World offshoots and codex deviants like BA, DA, SW, and DW. Take 6-10 Gravis models of any variety along with an apothecary and an ancient. Find some way of providing a FNP or Invulnerable save and plant them in cover. Makes for an extremely durable T5, 18-30 wound unit that can shoot/fight whenever it loses models and can regain slain models. Finally, it creates a roughly 3' ''dead zone'' on the board, as enemy units that get near it will be zapped with anywhere from 20-36 S4 or S5 bolter shots, potentially even double plasma or flamers. Finally, you can take another two squads for another 36-60 T5 wounds. Finally all of the Aggressors come with 3 attacks base and powerfists... 
** Three squads of Heavy Intercessors for god damn 90 T5 wounds can be done for 840 points. That's tougher than like ~30 Dark Eldar little fighter planes and packing 90 Attacks on the charge and up to 90 S5 shots, or 30 S5 AP-2 D2 shots, all with obsec.