Although Jenny Lewis has the lion’s share of lead singing in Rilo Kiley, there’s a fair number of songs sung by Blake Sennett.
Upon editing, I see that he was never on a single though.
In their heyday, Chicago had three lead singers: mellow-voiced Peter Cetera (“If You Leave Me Now”), middle-voiced Robert Lamm (“Saturday in the Park”), and gruff-voiced Terry Kath (“Make Me Smile”).
Then-bassist Randy Meisner sang (and wrote, I believe) Take It To The Limit on the original release (from the One of These Nights album).
For a more modern group, I think TV on the Radio split vocals between Tunde Adebimpe and Kyp Malone. They certainly have multiple singers (including a lot of guest vocalists).
Since the band changed lead singers before hitting it big, I can’t think of any song Natlie Maines doesn’t sing lead.
It’s not a big pop band, but Gaelic Storm splits lead singing between Patrick Murphy and Steve Twigger.
(They even had the female fiddle player sing a couple songs on one album, but since the group goes through female fiddle players like tissue paper, the most recent few don’t sing.)
Roxette has two singers. I think most of the hits were mainly Marie Fredriksson singing, though.
I think The Beautiful South are still recording…? And they have a male and female singer, who sing lead or share.
I think Blink 182 sometimes share lead also.
All three members of Husker Du sang lead (though bassist Greg Norton only did so rarely). For a somewhat more recent example, both Corrine Tucker and Carrie Brownstein of Sleater-Kinney sang lead, and all three members of Yo La Tengo do as well.
I know the OP mentions “bands nowadays”, but I wanted to get a mention in for The Cars. Rick Okasek sang most of the songs, but Benjamin Orr got the vox duties on hit songs like “Just What I Needed” and “Drive”.
R.E.M. has several songs that Mike Mills sang lead: “Superman,” “Texarkana,” and “Near Wild Heaven.”
Midnight Oil’s charismatic frontman was Peter Garrett but Rob Hirst sang lead on “When the Generals Talk” and “Kosciuszko.”
Squeeze had Glen Tilbrook (sweet melodic voice) and Chris Difford (froggy Cockney voice). And of course, their biggest song “Tempted” had yet another lead singer, Paul Carrack (formerly of Ace, and later of Mike + The Mechanics).
The B-52’s have songs with Fred Schneider, Cindy Wilson, and Kate Pierson sharing vocals or singing/speaking lead.
That seems to be a pattern with East Coast Canadian bands. Chris Murphy played drums in The Super Friendz for a while…he didn’t sing lead vocals with them but all three of the others in the band at the time (Matt Murphy, Charles Austin, Drew Yamada) did. Three of the five members of The Heavy Blinkers sang lead. All three of the members of The Hardship Post sang lead. All four of the members of Jale’s first lineup sang lead (and after Alison MacLeod left to join The Hardship Post, Mike Belitsky sang co-lead on a song on their last album). You get the picture.
Saw Old Crow Medicine Show on Austin City Limits, at least three of them sing lead on various songs. You gotta love a old-timey band with a guy named “Critter.” 
I’ll join your slight hijack and ad Van Halen (do backing vocals count?) , Derek Trucks , and most of the Kenny Wayne Shepard albums. (yeah, KWS sings some front vocals. but why bother when Noah Hunt is available)