Bind vectors across lists to single list of matrices

One option is to transpose the list of lists, then reduce the list elements to a single dataset with cbind.fill, get the transpose (t) and assign the row names to NULL

library(tidyverse)
library(rowr)
list(list1, list2, list3) %>% 
    transpose %>% 
    map(~ reduce(.x, cbind.fill, fill = NA) %>% 
          t %>% 
         `row.names<-`(NULL))
#$a
#     [,1] [,2] [,3] [,4] [,5]
#[1,]    1    2    3    4    5
#[2,]    1    2    3    4   NA
#[3,]    1    2    3   NA   NA

#$b
#     [,1] [,2] [,3] [,4] [,5]
#[1,]    6    7    8    9   10
#[2,]    6    7    8    9   NA
#[3,]    6    7    8   NA   NA

#$c
#     [,1] [,2] [,3] [,4] [,5]
#[1,]   11   12   13   14   15
#[2,]   11   12   13   14   NA
#[3,]   11   12   13   NA   NA

---

Or using base R

do.call(Map, c(f = function(...) {l1 <- list(...)
   do.call(rbind, lapply(l1, `length<-`, max(lengths(l1))))},  
      mget(paste0("list", 1:3))))

a data.table solution, just for fun:

plouf <- list(list1,list2,list3)

lapply(names(list1),function(name){
  lapply(plouf,function(x){
     as.data.table(t(x[[name]]))
     }) %>% 
    rbindlist(.,fill =T) %>%
`colnames<-`(NULL)
}) %>% setNames(names(list1))


$a

1:  1  2  3  4  5
2:  1  2  3  4 NA
3:  1  2  3 NA NA

$b

1:  6  7  8  9 10
2:  6  7  8  9 NA
3:  6  7  8 NA NA

$c

1: 11 12 13 14 15
2: 11 12 13 14 NA
3: 11 12 13 NA NA

the first loop is on the list name. The second loop loop is on the list of list, and extract the element of each list, transpose it into a data.table with unique row, to be able to use rbindlist which can fill missing columns.

without data.table, so similar but less good than what akrun proposed:

library(plyr)

lapply(names(list1),function(name){
  lapply(plouf,function(x){
    t(x[[name]])%>%
      as.data.frame
  }) %>% 
   rbind.fill %>%
    `colnames<-`(NULL)
}) %>% setNames(names(list1))

You may use 1. rapply to adjust the lengths of the sublists, and 2. t(mapply) to get the matrices by selecting with '[['.

listn <- list(list1, list2, list3)

setNames(lapply(seq(listn), function(x) 
  t(mapply(`[[`, rapply(listn, `length<-`, value=5, how="list"), x))), names(el(listn)))
# $a
#      [,1] [,2] [,3] [,4] [,5]
# [1,]    1    2    3    4    5
# [2,]    1    2    3    4   NA
# [3,]    1    2    3   NA   NA
# 
# $b
#      [,1] [,2] [,3] [,4] [,5]
# [1,]    6    7    8    9   10
# [2,]    6    7    8    9   NA
# [3,]    6    7    8   NA   NA
# 
# $c
#      [,1] [,2] [,3] [,4] [,5]
# [1,]   11   12   13   14   15
# [2,]   11   12   13   14   NA
# [3,]   11   12   13   NA   NA

In case the lengths are unknown use this code:

max(rapply(listn, length))
# [1] 5