Sivir build im actually trying atm .
Not lying im a fan of armor penetration and have a special rune page only focused on armor penetration .
9x lethality mark 9x attack damage seal 9x lethality glyph 3 lethality quintessence
12/18/0 mastery with thunderlord and with precision for the lethality for a total of 30 starting lethality .
My build is made so sivir deal lot of burst damage and his a midlane build . She has two tool for wave clear . Her Q and W . ( in 7.15 she gonna get a extra 30 damage per rank on her Q ) She has her shield whos really good against gank and not intensive caster who rely on their spell to roll stomp her enemy . Normally you will use it when they will use their cc etc or just ez mana gain . Shes really strong against AD assasin just because she outrange them and mitigate lot of their burst like talon . Her ultimate his wht make her so usefull especially if you want chasing ppl to finish the dirty job ;) and also provide MS steroid to all your time and subsequent collision .
So here my build im trying atm and i have lot of success with and really fun to play .
Berserker really important because it provide the AS you need to land your big chunk of HP auto attack ;) and work well with your ult passive.
Yoummu is the key of your build because the out of combat MS passive who will replace your boots in late game for another crit chance item if all goes well .
Duskblade because the lethality and will work well with the big chunk of damage you want to deal .
Lord oh lord dominik. ( work well against the armor item ppl will build against you especially in mid game and since your lethality will be negate by too much stacking it will help alot especially against tank and the extra damage you will deal against them .
Essence reaver for the cooldown reduction and also the attack damage it provide .
For the last item you will have two choice .
Infinite edge to deal extra damage and have your 40 % cooldown reduction
or guardian angel just for the passive and just change it later in the game for a infinite edge .
You can also replace your boots for
Just for the fast push and extra wave clear power ( Also its sweet in combat because it stack lot of damage with ricochet bounce but it but the two bolt doesnt proc ricochet only the primary attack ).
Phantom dancer for the extra movement speed in fight and the damage reduction and the boosting stat .
Why i especially like this build is because i feel the crit build need to much relying item around AD to work well with the multiple crit you could get from ricochet . I find it pretty hard to have a ult who make me go into fight and just try to clean up by relying on crit . This is why i made this build so i could roll stomp the adc or squishy before they kill me and have the upper hand .
Normally the stat i get from a crit build are the following at lvl 18 in the training tool .

400 ad 77 armor 1,29 attack speed ( 1,67 with ricochet active ) 70 % crit chance 15 ability power ( mastery ) 74 magic resist 30 % cooldown reduction and 399 ms (423 around enemy with phantom dancer and 468 with passive extra movement speed if you hit a enemy )
around 650 damage per crit auto and around 250 damage if you doesnt crit .

415 ad 77 armor 1,01 attack speed (1,39 with ricochet active) 40 % crit chance 15 ability power 39 magic resist 40 % cooldown reduction 380 ms ( 427 ms , 488 with youmuu active and your passive )
around 1000 damage per crit and 390 damage if you doesnt crit .
You can also change your
for
or
to upgrade your crit chance to 70 % while giving you more relying stat than
who only give a little as boost.
https://na.op.gg/summoner/userName=elysane Here my OP.gg to show wat matched i have done and im aware that im not a good player but i would never get those score with a crit build on sivir and going mid lane . I just wanted to share this build because its really fun and sivir get a buff next patch so i guess that it .