I installed all 624 apps from the store (as of today) on a Nexus 7 running vivid-proposed (image #42), and grepped through them to get a picture of which still use QtWebKit. Here’s a summary:

 - 15 applications import (and supposedly use) QtWebKit directly:

    com.nucleussystems.app.freshbookstimer
    com.ubuntu.developer.brianrobles204.karma-machine
    com.ubuntu.developer.carloalberto.randomimagesrel
    com.ubuntu.developer.fabricio.mnmo-counters
    com.ubuntu.developer.hansueli.burri.xkcd-viewer
    com.ubuntu.developer.larochelle.brian.feed-the-aggregator
    com.ubuntu.developer.mitya57.touchwriter
    com.ubuntu.developer.mzanetti.getmewheels2
    com.ubuntu.developer.penk.slatekit-shell
    com.ubuntu.developer.qqworini.aesyweibo
    com.ubuntu.developer.qtros.twimgo
    com.ubuntu.developer.yuntan.aztter
    com.ubuntu.developer.zaspire.cordova-mobilespec
    fr.skimbo.skimbou
    ir.oneapp.oneperday

 - 10 applications import (and supposedly use) Ubuntu.Components.Extras.Browser 0.1, i.e. QtWebKit under the hood:

    com.ubuntu.developer.andrewsomething.stackbrowser
    com.ubuntu.developer.daker.bytesjack
    com.ubuntu.developer.daker.x-type
    com.ubuntu.developer.fcole90.feedspot
    com.ubuntu.developer.karthik.upadya1.ifacebook
    com.ubuntu.developer.karthik.upadya1.igplus
    com.ubuntu.developer.karthik.upadya1.imail
    com.ubuntu.developer.mdspencer.project-dashboard
    com.ubuntu.developer.sangshuduo.doubanfmunofficial
    com.wellsb.esv-bible

 - 4 applications import Ubuntu.Components.Extras.Browser 0.2 (i.e. Oxide under the hood), they could use a rename of the import to Ubuntu.Web 0.2:

    com.ubuntu.developer.alaak.uberbag
    com.ubuntu.developer.filip-dobrocky.gagger
    com.ubuntu.developer.karthik.upadya1.wikipediatouch
    com.ubuntu.developer.rschroll.beru

 - 16 applications import Ubuntu.Web 0.2 (i.e. Oxide under the hood), no change needed:

    com.canonical.payui
    com.ubuntu.developer.bobo1993324.pdfjsviewer
    com.ubuntu.developer.mhall119.ureadit
    com.viclog.2048
    com.ubuntu.developer.bobo1993324.udropcabin
    com.ubuntu.developer.danielholm.pingpong
    com.ubuntu.developer.dholbach.randomcats
    com.ubuntu.developer.mdspencer.project-dashboard
    com.ubuntu.developer.mlosli.panpipe
    com.ubuntu.developer.mzanetti.ubuntu-fitbit-app
    com.ubuntu.developer.qtros.yad
    com.ubuntu.developer.rayalez.hackernews
    com.ubuntu.developer.roman2861.zmusic
    com.ubuntu.developer.turan.mahmudov.ufoursquare
    com.viclog.flappybird
    cx.gould.ted.ubuntu-app-startup

 - 12 applications import com.canonical.Oxide, no change needed:

    com.ubuntu.reminders
    com.popey.calculator
    com.popey.sst
    com.ubuntu.developer.danielholm.stumble
    com.ubuntu.developer.dobey.delta-web
    com.ubuntu.developer.dpniel.dekko
    com.ubuntu.developer.mkamenjak77.4chanappextra
    com.ubuntu.developer.mkamenjak77.bluedragonbrowser
    com.ubuntu.developer.mkamenjak77.bugapp
    com.ubuntu.developer.mkamenjak77.googleplusapp
    com.ubuntu.developer.nathanosman.twobuntu-app
    com.ubuntu.developer.rschroll.beru

 - Additionally, there are still 15 webapps using version 1.0 of the policy, meaning they still use QtWebKit when run in the webapp container. Updating them to version 1.1 of the policy will make them run with Oxide:

    com.and.maps
    com.lastpass.lpubuntu
    com.ubuntu.developer.adrian-arroyocalle.social-share
    com.ubuntu.developer.cwayne18.baidu
    com.ubuntu.developer.cwayne18.renren
    com.ubuntu.developer.cwayne18.weibo
    com.ubuntu.developer.danielholm.swedbank
    com.ubuntu.developer.danielholm.tradera
    com.ubuntu.developer.geistschatten.social-groovy
    com.ubuntu.developer.hughisaacs2.acrylicstyle
    com.ubuntu.developer.nervatura.nervatura-mobile-client
    com.ubuntu.developer.victorsemyonov.mymaps
    net.launchpad.click-webapps.lloyds-bank-uk
    net.launchpad.click-webapps.tumblr
    net.launchpad.click-webapps.xkcd