What are solid chess openings that starts with 1.d4?

I'm generally a queen's pawn player and I did try to learn some 1.e4 openings but I lost every one of them so far. I wanna try some queen's pawn openings or maybe even a flank pawn opening, as long as they're solid. However, I can't find a lot of videos that lists solid 1.d4 openings ( most of the time)

#1
Queen's Gambit 1 d4 2 c4 and London System 1 d4 2 Bf4 are solid.

It's true that 1.d4 openings are solid - you're unlikely to lose in the opening, and that should give you confidence. The London is good, but perhaps the Colle is even easier to learn - you just put your kniight on f3, your pawn on e3. your bishop on d3, further support the d-pawn with c3, play your other knight to d2, castle short and play Re1, with ideas incuding an e4 break, an aggresive knight on e5 and/or a bishop sac on h7. Other people will no doubt say that you shouldn't play these moves automatically, that there are some cases where they're not the best, and that system openings like the Colle won't in the long run improve your chess. They're right, but if you're having a hard time in the opening at present this will get you into the middle-game relatively unharmed and then you can concentrate on playing as well as you can.

You cannot use the Colle as a catchall structure.  There is a reason that there is this thing called the "anti-Colle".

To play any opening, you need to understand why you are playing it and why it is right.

White's whole idea in the Colle is to dominate control of e5 with a Black pawn on e6, so as not to allow ...e5, and to LOCK THE BLACK BISHOP BEHIND THE PAWN CHAIN!!!  White places his Bishop on d3 to attack h7, not to trade it off.

After 1.d4 d5 2.Nf3 Nf6 3.e3, ONLY if Black plays 3...e6 is the Colle playable.

After 3...Bf5 (or 3...Bg4), WHITE MUST play 4.c4 or he is worse.  After 4...c6, you have a direct transposition to the Slow Slav.

If you have no interest in such transpositions, the Colle is NOT for you.  After 1.d4 d5 2.Nf3 Nf6 3.e3 Bf5 4.Bd3? Bxd3 5.Qxd3, White is slightly worse as Black removed his bad Bishop for White's good one.  It would give White the same problem as what Black faces if he just freely trades dark squared bishops early on in the French or Stonewall Dutch.

The Colle is fine to go with if you understand this stipulation that you MUST play 4.c4 if Black brings the light-squared Bishop outside the pawn chain or at least delays ...e6.  Like 1.d4 d5 2.Nf3 Nf6 3.e3 c6, once again, only move is 4.c4 (4.Bd3 Bg4 5.c4 could cost White a tempo if Black plays ...dxc4).

After 3...e6, now 4.Bd3 is perfectly fine, and White can answer 4...c5 with the Koltinowski (5.c3) or the Zukertort (5.b3).  The first gives the Bishop the c2 square if Black plays ...c4 and the latter prevents ...c4.

@ThrillerFan, the OP has a rating of 786. Colle against everything may not be advisable at a higher level, but when you're falling into traps in the first few moves, a Colle formation is easy to remember and won't lose outright. No point in advising someone to run before they can walk.

queens gambit, london system, catalan (mabye a bit too advanced) if you want to do a flank pawn opening go for the english 1.c4. 

In my opinion the best option would be the london system, or the queens gambit as both are solid, and are my personal preferences if i want something solid.

I'm seeing suggestions of the colle system. I think it is also great, but if you are going to play that kind of structure, i would recommend liberating the dark squared bishop and go for a london system.

If you like the feel of d4 openings but want more variety, then I recommend looking into 1. c4.   Much like d4, it typically leads to semi-open positions with interesting pawn breaks. You'd probably like fianchettoing your bishop with g3 and Bg2. This will generally give you a good, solid position that will get you to a decent middlegame without too many hairy tactics.

Interesting

I enjoy it!

But it’s not for everybody.

As everyone already stated, London... learn Stonewall too, to accompany it. Queen's Gambit... the higher evolution of London, in a sense, and a super serious opening of the highest order. Catalan, it's a fianchetto verzzzzzzzzzzzzzzzzzzzzzz! Oh, huh... what? Oh, Catalan... yes, solid... Solid solid...

Introduction To The London System & Jobava London System...

https://www.chess.com/blog/RussBell/the-london-system

The Stonewall Attack...

https://www.chess.com/blog/RussBell/stonewall-attack

I'm back. I decided to play the English Defense since I already play the London System, and oh boy. The English is basically OP, beat a couple of 1000's, beat a lot of high 900's, 1 1200 and 1 1300 as of now with the English Defense. It also gave me 130+ elo points. Hunting for the 1k rating now. ( btw I was 800 before I started playing the english)

i would have suggested playing both the stonewall attack and defense, but opponents are pulling a lot of new anti-stonewall systems out of their hats and tripping me up losing by 10 bad. it used to be easy to drag an 1800 on to move 40 before anything got messy a couple decades ago.