Most of the sideboard cards are taken in considering versatility since we run a mono-coloured deck, so most cards will have different uses against different kinds of decks, i.e.
Echoing Truth
works against
Chalice of the Void
decks and also against
Dark Depths
decks.
When considering what to take out, you must remember that
Stifle
and
Vision Charm
are both combo pieces, but they have different utilities in different matchups as
Stifle
is mainly used as mana denial by countering fetch lands and
Vision Charm
can be used to fizzle removal spells.
Always remember that your Sideboard must be effective against your local meta, so maybe you might not want to copy mine entirely, so I just added a briefly explanation on the cards I chose for my version:
• 1x
Back to Basics
= Basically against Lands, 12-post, Grixis Delver and decks that rely too heavily on non-basic lands, you can potentially run more of these and even in the mainboard depending on your local meta.
• 1x
Blue Elemental Blast
= Good against Red decks in general (duh!) like Moon Stompy, 4C/Grixis Control, UR Delver, Sneak n' Show, RUG Delver (specially now with W6) and you may even side it in against Storm so you can counter
Past in Flames
• 1x
Dismember
= Creature decks in general, but it is very useful against key creatures that may stop our combo like
Qasali Pridemage
,
Goblin Trashmaster
,
Goblin Cratermaker
or creatures with massive threat potential like
Monastery Mentor
,
Tarmogoyf
, etc
• 2x
Echoing Truth
= The bounce factor matters a lot here since we can use it to remove
Chalice of the Void
which wrecks our deck and
Ensnaring Bridge
as well, also very useful against certain combo decks like Reanimator and Turbo Depths and another practical use of this card is getting rid of multiple Tokens all at once!
• 1x
Flusterstorm
= With the amount of counterspells in this deck it is inevitable that we find ourselves in some counter wars and this card just wins counter wars, plain and simple. Added bonus for also being good against Storm!
• 1x
Grafdigger's Cage
= Answer for GY strats like Dredge, Reanimator, etc and also has an interesting function disabling cards that work like Green's Sun Zenith and
Birthing Pod
• 1x
Hydroblast
= Same as
Blue Elemental Blast
, but it is good to split the copies between these cards with different names so you can avoid being hit by cards like
Cabal Therapy
,
Meddling Mage
and
Nevermore
• 1x
Misdirection
= Another tool to win Counter Wars as well as change the target of removal spells going torwards your
Phyrexian Dreadnought
, this works even against
Abrupt Decay
and is amazing against discard spells, special mention to
Hymn to Tourach
as it feels great to redirect it at your opponents face lol
• 1x
Pithing Needle
= Most versatile card here, you can shut down cards from fetch lands to planeswalkers and it will have a fair use against a good range of decks in Legacy overall, but the ones worth mentioning are: Depths Decks since you can stop either
Thespian's Stage
or
Vampire Hexmage
from activating, Blade decks since you can stop almost everything they have in common like
Stoneforge Mystic
,
Umezawa's Jitte
,
Jace, the Mind Sculptor
, etc
• 2x
Ratchet Bomb
= Awesome card against
Chalice of the Void
as you can destroy it immediately, also great against Tokens for the same reason and can be used to snipe other permanents as well as long as you can buy the time to add up the counters
• 1x
Submerge
= Great against
Dark Depths
and allows you to spend your whole mana every turn while holding it in hand, also worth mentioning that since it puts the creature on top of library it can be used in response to shuffle effects from your opponent and it will basically work as a single target
Terminus
if you target a
Glistener Elf
or something like that
• 2x
Surgical Extraction
Amazing Graveyard Hate and also awesome card to strip down a deck from its main card (like removing
Dark Depths
from BG Depths) or piece of removal that gets in our way like
Swords to Plowshares
,
Fatal Push
or
Abrupt Decay